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| Control | Property | Setting |
| Form | Name | frmGraph |
| Caption | Graph Data | |
| Height | 3375 | |
| Left | 2145 | |
| Top | 1710 | |
| Width | 5280 | |
| Graph | Name | Graph1 |
| Height | 2415 | |
| Left | 120 | |
| Top | 120 | |
| Width | 4935 | |
| BorderStyle | 1-Fixed Single | |
| CommonDialog | Name | CommonDialog1 |
| Caption | Menu |
| &File | mnuFile |
| &Save | mnuFileItem(0) |
| &Copy | mnuFileItem(1) |
| - | mnuFileItem(2) |
| mnuFileItem(3) | |
| Print Set&Up | mnuFileItem(4) |
| - | mnuFileItem(5) |
| E&xit | mnuFileItem(6) |
| &View | mnuView |
| &Pie Chart | mnuViewItem(0) |
| &Bar Graph | mnuViewItem(1) |
| &Line Chart | mnuViewItem(2) |
| &Area Graph | mnuViewItem(3) |
You need to add some code to this form. But first, save it (FRMGRAPH.FRM) and save the project (PRJDATAGRAPH.VBP). Then add the code in Listing 11.7 to the Form_Load event of the project. This sets the default size of the form to fill 75% of the screen.
Private Sub Form_Load()
`
` set initial form size
`
If Me.WindowState = vbNormal Then
Me.Width = Screen.Width * 0.75
Me.Height = Screen.Height * 0.75
End If
`
End Sub
Now, add the code from Listing 11.8 to the Form_Resize event. This code
allows users to resize the graph by resizing the form.
Private Sub Form_Resize()
`
` make graph fill the form
`
Graph1.Left = 1
Graph1.Top = 1
Graph1.Width = Me.ScaleWidth
Graph1.Height = Me.ScaleHeight
`
End Sub
The code in Listing 11.9 goes in the mnuFileItem_Click event. This code
is executed each time the user selects one of the File menu items. The Index value
returns the item number selected by the user. You code the CopyGraph and
SaveGraph methods in just a moment.
Private Sub mnuFileItem_Click(Index As Integer)
`
` handle file menu selections
`
Select Case Index
Case 0 ` save
GraphSave
Case 1 ` copy
GraphCopy
Case 2 ` separator
` no action
Case 3 ` print
Me.PrintForm
Case 4 ` printer setup
CommonDialog1.ShowPrinter
Case 5 ` separator
` no action
Case 6 ` exit
Unload Me
End Select
`
End Sub
Now add the code in Listing 11.10 to the mnuViewItem_Click event. This allows
users to select the type of graph they view.
Private Sub mnuViewItem_Click(Index As Integer)
`
` handle view selections
`
Dim intGraphType As Integer
`
Select Case Index
Case 0 ` pie chart
intGraphType = gphPie3D
Case 1 ` bar graph
intGraphType = gphBar3D
Case 2 ` line chart
intGraphType = gphLine
Case 3 ` area graph
intGraphType = gphArea
End Select
`
Graph1.GraphType = intGraphType
Graph1.DrawMode = gphDraw
`
End Sub
Now you're ready to code the GraphCopy method. The code in Listing 11.11
is all you need to copy the graph image to the Windows Clipboard. You can then paste
this image of the graph from the Clipboard to any other Windows program that allows
image cut and paste operations (Microsoft Write, for example).
Public Sub GraphCopy()
`
` copy graph to clipboard
`
Graph1.DrawMode = gphBlit
Graph1.DrawMode = gphCopy
Graph1.DrawMode = gphDraw
`
MsgBox "Graph has been copied to the clipboard", _
vbInformation, _
"Copy Graph"
`
End Sub
Next, add the GraphSave method code from Listing 11.12 to the project. This
code prompts the user for a filename and saves the current graph under that filename.
Public Sub GraphSave()
`
` save graph to disk file
`
Dim strFileName As String
`
CommonDialog1.DefaultExt = ".bmp"
CommonDialog1.DialogTitle = "Save Graph"
CommonDialog1.Filter = "Bitmap Files | *.bmp"
CommonDialog1.ShowSave
strFileName = CommonDialog1.filename
`
If Trim(strFileName) <> "" Then
Graph1.DrawMode = gphBlit
Graph1.ImageFile = strFileName
Graph1.DrawMode = gphWrite
Graph1.DrawMode = gphDraw
End If
`
End Sub
That's all the code you need for the form. Save this form now. Next, you create the
routine that calls this form.
In order to display the form you just created, you need to create a class object that allows users to set some properties and executes a ShowGraph method. The basic properties of the DataGraph object are
This is a simple graph tool that is capable of displaying a single-set, multipoint dataset in the most commonly used graph types. Modifications can be made to this routine to add additional labeling, legends, and text. You could also add options in order to graph more than one set of data per graph. For now, just keep the project simple. When you complete this project, you can add your own modifications.
First, you need to add some local storage variables to the class. These contain the passed properties along with a couple of local variables needed for Private methods. Add the code from Listing 11.13 to the class.
Option Explicit
`
` enumerated graph types
`
Enum dgType
dgPie3d = gphPie3D
dgBar3d = gphBar3D
dgLine = gphLine
dgArea = gphArea
End Enum
`
` local property storage
`
Private intGraphType As Integer
Private strDBName As String
Private strSQLSelect As String
Private strFieldPoint As String
Private strTitle As String
`
` for internal use only
Private ws As Workspace
Private db As Database
Private rs As Recordset
Private lngNumPoints As Long
Private lngLoop As Long
`
Notice the use of the Enum..End Enum construct in the declarations section.
This is a special type of constant declaration that combines a user-defined type
(dgType) with a set of predefined values (dgPie3D, dgBar3D, dgLine, dgArea). When
you use this class object in your programs, you can see the enumerated types in the
code-complete windows that appear as you enter the source code.
Now you need to declare Public properties of the class. These properties allow users to manipulate the local storage variables of the class. Note that all five properties are included in Listing 11.14. You need to add each property individually using the Tools | Add Procedure | Property options from the main menu.
Public Property Get GraphType() As Integer
GraphType = intGraphType
End Property
Public Property Let GraphType(ByVal vNewValue As Integer)
If IsNumeric(vNewValue) Then
intGraphType = Int(vNewValue)
End If
`
If intGraphType < 1 Or intGraphType > 11 Then
Err.Raise 380 ` invalid property
intGraphType = 0
End If
`
End Property
Public Property Get DatabaseName() As String
DatabaseName = strDBName
End Property
Public Property Let DatabaseName(ByVal vNewValue As String)
strDBName = vNewValue
End Property
Public Property Get SQLSelect() As String
SQLSelect = strSQLSelect
End Property
Public Property Let SQLSelect(ByVal vNewValue As String)
strSQLSelect = vNewValue
End Property
Public Property Get GraphField() As String
GraphField = strFieldPoint
End Property
Public Property Let GraphField(ByVal vNewValue As String)
strFieldPoint = vNewValue
End Property
Public Property Get GraphTitle() As String
GraphTitle = strTitle
End Property
Public Property Let GraphTitle(ByVal vNewValue As String)
strTitle = vNewValue
End Property
Notice some error-checking code in the GraphType property Let method. This
checks for a valid graph type and reports an error if a valid value is not found.
Now add the code from Listing 11.15 to the Class_Initialize event. This sets the default values for the properties.
Private Sub Class_Initialize()
`
` set startup values
`
strDBName = ""
strSQLSelect = ""
strFieldPoint = ""
strTitle = "Data Graph"
intGraphType = gphBar3D
`
End Sub
Now you're ready to code the ShowGraph method. This one method collects
all the property values, creates a dataset, and builds a graph based on the data.
Create a Public Sub called ShowGraph in the class and add the code
from Listing 11.16.
Public Sub ShowGraph()
`
` display graph
`
On Error GoTo LocalErr
`
Screen.MousePointer = vbHourglass
OpenDB
InitGraph
LoadGraphData
Screen.MousePointer = vbNormal
`
frmGraph.Graph1.DrawMode = gphDraw
frmGraph.Show vbModal
`
Exit Sub
`
LocalErr:
Err.Raise vbObjectError + 4, App.EXEName, "Error displaying graph"
`
End Sub
This method calls three other Private methods. Create the Private Sub OpenDB
and add the code from Listing 11.17.
Private Sub OpenDB()
`
` open database/recordset
`
On Error GoTo LocalErr
`
Set ws = dbengine.Workspaces(0)
Set db = ws.OpenDatabase(strDBName)
Set rs = db.OpenRecordset(strSQLSelect, dbOpenSnapshot)
`
Exit Sub
`
LocalErr:
Err.Raise vbObjectError + 1, App.EXEName, "Error creating data set"
`
End Sub
Next, add the Private Sub InitGraph and enter the code from Listing 11.18.
This code loads the frmGraph form and sets the initial values of the display.
Private Sub InitGraph()
`
` initialize the graph form
`
On Error GoTo LocalErr
`
rs.MoveLast
lngNumPoints = rs.RecordCount
`
Load frmGraph
frmGraph.Graph1.GraphType = intGraphType
frmGraph.Graph1.GraphTitle = strTitle
frmGraph.Graph1.NumSets = 1
frmGraph.Graph1.NumPoints = lngNumPoints
frmGraph.Graph1.AutoInc = 1
`
Exit Sub
`
LocalErr:
Err.Raise vbObjectError + 2, App.EXEName, "Error intializing graph form"
`
End Sub
Finally, add the Private Sub LoadGraphData to the class. This is the code
that moves the data from the Recordset into the graph control (see Listing 11.19).
Private Sub LoadGraphData()
`
` fill graph with data
`
On Error GoTo LocalErr
`
rs.MoveFirst
For lngLoop = 1 To lngNumPoints
frmGraph.Graph1.GraphData = rs.Fields(strFieldPoint)
rs.MoveNext
Next
`
Exit Sub
`
LocalErr:
Err.Raise vbObjectError + 3, App.EXEName, "Error loading graph data"
`
End Sub
That's all there is to it. You now have a reusable data graphing OLE Server. All
you need to do now is save the project and compile the DLL. You can do this by selecting
File | Make prjDataGraph.DLL from the main menu. In the next section, you test this
library with a simple example.
You need to build a short program to test your new library. Suppose you have just been told that the marketing department needs a tool to display the year-to-date book sales by sales representative. The data already exists in a database, but there is no easy way to turn that data into a visual display that upper-level management can access on a regular basis. You have been asked to quickly put together a graphing front-end for the sales data.
In order to complete the job, you need to initialize a copy of the DataGraph object; set the DatabaseName and SQLSelect properties; set the GraphType, GraphField, and GraphTitle properties; and then execute the ShowGraph method. From there, users can select various graph styles and, if they wish, save the graph to disk, send it to the printer, or copy it to the Clipboard to paste in other documents.
Because you already have the completed graph library, you can complete your assignment with as few as 10 lines of Visual Basic code.
First, if you don't have it running right now, start Visual Basic and create a new Standard EXE project. If you still have Visual Basic up from the last section of this chapter, select File | Add Project... to add a new Standard EXE project. Make this new project the Default startup project, too.
Now, select Project | References and locate and select the prjDataGraph library. This links your new project with the OLE Server DLL that you built earlier in this chapter.
Add a single button to a blank form. Set its Name property to cmdRepSales and its Caption property to &RepSales. Add the code from Listing 11.20 to support the button.
Private Sub cmdRepSales_Click()
`
` test graph libaray
`
Dim objDG As Object
`
Set objDG = New DataGraph
`
objDG.DatabaseName = App.Path & "\..\..\data\books5.mdb"
objDG.sqlselect = "SELECT SalesRep, SUM(Units) AS UnitsSold FROM BookSales GROUP BY SalesRep"
objDG.graphfield = "UnitsSold"
objDG.graphTitle = "Units Sold by Sales Rep"
`
objDG.showgraph
`
End Sub
This code example sets a few properties and then calls the ShowGraph method.
That's all there is to it! Save this form as FRMTEST.FRM and the project
as PRJTEST.VBP. Now run the project. After you click the single command
button, you see the graph displayed on-screen. Your screen should look something
like the one shown in Figure 11.11.
You have just completed your first database graphing project using the new OLE
Server! Before you end your work on this OLE Server, let's add a few new properties
to the class object. These give you (and our users) greater control over the graph
display.
Figure
11.11. A graph of book sales data by sales
rep.
Now that the basic DataGraph object is working, let's add some of the bells and whistles that make this a versatile programming tool. Let's add four new properties to the class:
In order to add these new features, all you need to do is add the property definitions to the DataGraph object and then add code to the ShowGraph method to incorporate these new properties into the displayed graph.
The code in Listing 11.21 shows the changes you need to make to the general declaration section of the DataGraph class. The four new variables are added at the end of the section.
Option Explicit
`
` enumerated graph types
`
Enum dgType
dgPie3d = gphPie3D
dgBar3d = gphBar3D
dgLine = gphLine
dgArea = gphArea
End Enum
`
` local property storage
`
Private intGraphType As Integer
Private strDBName As String
Private strSQLSelect As String
Private strFieldPoint As String
Private strTitle As String
`
` for internal use only
Private ws As Workspace
Private db As Database
Private rs As Recordset
Private lngNumPoints As Long
Private lngLoop As Long
`
` added properties
Private strLegendField As String
Private strLabelField As String
Private strLeftTitle As String
Private strBottomTitle As String
`
The next step is to use the Tools | Add Procedure | Property options from the main
menu to add the four new property declarations to the class. Listing 11.22 shows
the code for each of these new properties.
Public Property Get LegendField() As Variant
LegendField = strLegendField
End Property
Public Property Let LegendField(ByVal vNewValue As Variant)
strLegendField = vNewValue
End Property
Public Property Get LabelField() As Variant
LabelField = strLabelField
End Property
Public Property Let LabelField(ByVal vNewValue As Variant)
strLabelField = vNewValue
End Property
Public Property Get LeftTitle() As Variant
LeftTitle = strLeftTitle
End Property
Public Property Let LeftTitle(ByVal vNewValue As Variant)
strLeftTitle = vNewValue
End Property
Public Property Get BottomTitle() As Variant
BottomTitle = strBottomTitle
End Property
Public Property Let BottomTitle(ByVal vNewValue As Variant)
strBottomTitle = vNewValue
End Property
Because just about any string value could be valid for these properties, no error
checking is done at the time the properties are set. In a production application,
you might want to add error-checking to protect users.
After adding the new properties, you need to update the Class_Initialize event to set the new properties at the start of the object. Listing 11.23 shows the code you need to add to the Class_Initialize event.
Private Sub Class_Initialize()
`
` set startup values
`
strDBName = ""
strSQLSelect = ""
strFieldPoint = ""
strTitle = "Data Graph"
intGraphType = dgBar3D
`
` initialize added properties
`
strLegendField = ""
strLabelField = ""
strBottomTitle = ""
strLeftTitle = ""
`
End Sub
Now you need to build routines to add the legends and labels to the graph. Create
a Private Sub method called AddLegends and enter the code from
Listing 11.24.
Private Sub AddLegends()
`
` add legends to the existing graph
`
If Trim(strLegendField) = "" Then Exit Sub
`
frmGraph.Graph1.AutoInc = 1
`
rs.MoveFirst
For lngLoop = 1 To lngNumPoints
frmGraph.Graph1.LegendText = rs.Fields(strLegendField)
rs.MoveNext
Next
`
End Sub
Notice the first line of code in Listing 11.24. The line checks to see whether the
strLegendField variable contains any printable data. If not, the Exit
Sub is executed. No reason to set the legends if no LegendField has been set!
Now add the Private Sub called AddLabels to your class. The code in Listing 11.25 should be added to this new method.
Private Sub AddLabels()
`
` add labels to the existing graph
`
If Trim(strLabelField) = "" Then Exit Sub
`
frmGraph.Graph1.AutoInc = 1
`
rs.MoveFirst
For lngLoop = 1 To lngNumPoints
frmGraph.Graph1.LabelText = rs.Fields(strLabelField)
rs.MoveNext
Next
`
End Sub
Next, you need to add the Private Sub called AddTitles to the class.
This sets the left and bottom title properties of the graph. Listing 11.26 contains
the code needed for this method. Note that the variables strLeftTitle and
strBottomTitle are checked for valid data before the graph properties are
actually set.
Private Sub AddTitles()
`
` add left and bottom titles
`
If Trim(strLeftTitle) <> "" Then
frmGraph.Graph1.LeftTitle = strLeftTitle
End If
`
If Trim(strBottomTitle) <> "" Then
frmGraph.Graph1.BottomTitle = strBottomTitle
End If
`
End Sub
Finally, it's time to modify the ShowGraph method to incorporate the new
methods into your graph display. Listing 11.27 shows the updated ShowGraph
method.
Public Sub ShowGraph()
`
` display graph
`
On Error GoTo LocalErr
`
Screen.MousePointer = vbHourglass
OpenDB
InitGraph
LoadGraphData
`
` added property handling
AddLegends
AddLabels
AddTitles
`
Screen.MousePointer = vbNormal
`
frmGraph.Graph1.DrawMode = gphDraw
frmGraph.Show vbModal
`
Exit Sub
`
LocalErr:
Err.Raise vbObjectError + 4, App.EXEName, "Error displaying graph"
`
End Sub
Now all you need to do is modify the cmdSalesRep_Click event of the frmTest
form to test out these new properties. Switch to the prjTest project and add the
code from Listing 11.28 to the cmdSalesRep_Click event.
Private Sub cmdRepSales_Click()
`
` test graph libaray
`
Dim objDG As Object
`
Set objDG = New DataGraph
`
objDG.DatabaseName = App.Path & "\..\..\data\books5.mdb"
objDG.sqlselect = "SELECT SalesRep, SUM(Units) AS UnitsSold FROM BookSales GROUP BY SalesRep"
objDG.graphfield = "UnitsSold"
objDG.graphTitle = "Units Sold by Sales Rep"
`
` added properties
objDG.labelfield = "SalesRep"
objDG.lefttitle = "Units Sold"
objDG.bottomtitle = "Sales Reps"
objDG.legendfield = "SalesRep"
`
objDG.showgraph
`
End Sub
Save and run the PRJTEST.VBP project. When you click the SalesRep button,
your screen should look like the one shown in Figure 11.12.
Figure
11.12. Viewing the updated graph object
display.
As soon as you confirm that the modifications to the DataGraph object work without
errors, recompile the ActiveX DLL. You can use this OLE Server DLL in all your future
VBA projects. As an example, you can now add some graphs to the CompanyMaster project
you started last week.
For the last project of the day, you add three graphs to the CompanyMaster project:
First you have to add a new menu item to the CompanyMaster form that calls the graphs. Then you need to construct SQL statements that select the desired data and feed it to the graph object.
Adding the graph menu items is pretty easy. First, load the MASTER.VBP
project from the CHAP11\COMASTER directory. Add the graph object to the
project by selecting Project | References and locating and adding the Databound Graph
object library (see Figure 11.13).
Figure
11.13. Adding the Databound Graph object library.
Use Table 11.3 as a guide for adding the following menu items to the CompanyMaster
menu.
Table 11.3. Added menu items for the CompanyMaster main menu.
| Caption | Menu |
| &Graphs | mnuGraphs |
| Sales by &Region | mnuGraphsItem(0) |
| Sales by &Month | mnuGraphsItem(1) |
| Sales by &Customer | mnuGraphsItem(2) |
To get the total customer sales by region, you use the following SQL SELECT statement:
SELECT Region, SUM(Amount) AS SalesTotal FROM SalesData WHERE CompanyName<>'Budget' GROUP BY Region
This is the SQL statement you use to generate the Snapshot object that is passed to the graph library. Place Listing 11.29 in the mnuGraphsItem Click event.
Private Sub mnuGraphsItem_Click(Index As Integer)
`
` handle graph menu requests
`
Dim objDG As New DataGraph
Dim strSQL As String
`
Select Case Index
Case 0 ` sales by region
`
strSQL = "SELECT Region, SUM(Amount) AS SalesTotal FROM "
strSQL = strSQL & "SalesData WHERE CompanyName<>'Budget' GROUP BY ÂRegion"
`
objDG.DatabaseName = Data1.DatabaseName
objDG.SQLSelect = strSQL
objDG.GraphType = dgPie3d
objDG.GraphField = "SalesTotal"
objDG.GraphTitle = "Sales by Region"
objDG.LegendField = "Region"
`
Case 1 ` sales by month
Case 2 ` sales by customer
End Select
`
objDG.ShowGraph
`
End Sub
Notice that you used the SQL statement you defined earlier as the SQLSelect property
of the DataGraph object. The rest of the code should be familiar by now: You set
several properties that are required for the graph object library and then you called
the ShowGraph method.
NOTE: It is important to keep in mind that you did not have to load the GRAPH32.OCX file into your project. Because this is part of the ActiveX DLL, you do not need to identify it in the Visual Basic project that uses the DLL. The OCX, and its supporting files, must be present on your machine, but you do not have to add it to your project.
Now, save and run the project. When you select Graph | Sales by Region from the
main menu, you should see a graph like the one shown in Figure 11.14.
Figure
11.14. Displaying the Sales by Region
pie graph.
You can resize the form and the graph resizes too. You can also use the menu on the
graph to print, save, or copy the graph to the Clipboard.
Now add the Sales by Month graph to the project. This time, you want a line graph that shows the total sales by month. First, you need to construct the SQL statement. It should look like the following:
SELECT Month, SUM(Amount) AS SalesTotal FROM SalesData WHERE CompanyName<>'Budget' GROUP BY Month;
Now open the mnuGraphsItem_Click event and add the code in Listing 11.30.
Private Sub mnuGraphsItem_Click(Index As Integer)
`
` handle graph menu requests
`
Dim objDG As New DataGraph
Dim strSQL As String
`
Select Case Index
Case 0 ` sales by region
`
strSQL = "SELECT Region, SUM(Amount) AS SalesTotal FROM "
strSQL = strSQL & "SalesData WHERE CompanyName<>'Budget' GROUP BY ÂRegion"
`
objDG.DatabaseName = Data1.DatabaseName
objDG.SQLSelect = strSQL
objDG.GraphType = dgPie3d
objDG.GraphField = "SalesTotal"
objDG.GraphTitle = "Sales by Region"
objDG.LegendField = "Region"
`
Case 1 ` sales by month
`
strSQL = "SELECT Month, SUM(Amount) AS SalesTotal FROM "
strSQL = strSQL & "SalesData WHERE CompanyName<>'Budget' GROUP BY ÂMonth"
`
objDG.DatabaseName = Data1.DatabaseName
objDG.SQLSelect = strSQL
objDG.GraphType = dgLine
objDG.GraphField = "SalesTotal"
objDG.LabelField = "Month"
objDG.GraphTitle = "Sales by Month"
objDG.LeftTitle = "($)"
objDG.BottomTitle = "Months"
`
Case 2 ` sales by customer
End Select
`
objDG.ShowGraph
`
End Sub
The only real difference here is the new SQL statement and the settings for the titles,
labels, and legends. Save and run this code. Check your resultant graph with the
one shown in Fig-ure 11.15.
Figure
11.15. Displaying the Sales by Month line
graph.
Finally, add the Sales by Company bar graph to the CompanyMaster project. Here is
the SQL statement you need to produce a dataset that contains the year-to-date sales
figures by company:
SELECT CompanyName, SUM(Amount) AS SalesTotal FROM SalesData WHERE CompanyName<>'Budget' GROUP BY CompanyName;
Now modify the mnuGraphsItem_Click event to match the code in Listing 11.31.
Private Sub mnuGraphsItem_Click(Index As Integer)
`
` handle graph menu requests
`
Dim objDG As New DataGraph
Dim strSQL As String
`
Select Case Index
Case 0 ` sales by region
`
strSQL = "SELECT Region, SUM(Amount) AS SalesTotal FROM "
strSQL = strSQL & "SalesData WHERE CompanyName<>'Budget' GROUP BY ÂRegion"
`
objDG.DatabaseName = Data1.DatabaseName
objDG.SQLSelect = strSQL
objDG.GraphType = dgPie3d
objDG.GraphField = "SalesTotal"
objDG.GraphTitle = "Sales by Region"
objDG.LegendField = "Region"
`
Case 1 ` sales by month
`
strSQL = "SELECT Month, SUM(Amount) AS SalesTotal FROM "
strSQL = strSQL & "SalesData WHERE CompanyName<>'Budget' GROUP BY ÂMonth"
`
objDG.DatabaseName = Data1.DatabaseName
objDG.SQLSelect = strSQL
objDG.GraphType = dgLine
objDG.GraphField = "SalesTotal"
objDG.LabelField = "Month"
objDG.GraphTitle = "Sales by Month"
objDG.LeftTitle = "($)"
objDG.BottomTitle = "Months"
`
Case 2 ` sales by customer
`
strSQL = "SELECT CompanyName, SUM(Amount) AS SalesTotal FROM "
strSQL = strSQL & "SalesData WHERE CompanyName<>'Budget' GROUP BY ÂCompanyName"
`
objDG.DatabaseName = Data1.DatabaseName
objDG.SQLSelect = strSQL
objDG.GraphType = dgBar3d
objDG.GraphField = "SalesTotal"
objDG.LegendField = "CompanyName"
objDG.LabelField = "SalesTotal"
objDG.GraphTitle = "Sales by Company"
objDG.LeftTitle = "($)"
objDG.BottomTitle = "Companies"
`
End Select
`
objDG.ShowGraph
`
End Sub
Again, the only real difference is in the SQL statement and the titles, labels, and
legends. Save and run the project. Your Sales by Company graph should look like the
one in Figure 11.16.
Figure
11.16. Displaying the Sales by Company
bar graph.
Today you learned how to use the graph control that ships with Visual Basic in order to create visual displays of your data tables. You learned how to add the control to your project and how to load the graph control with data points, titles, legends, and labels.
Also, you built a graph ActiveX DLL Object Library that you can use to display virtually any dataset in a variety of graph formats. This library lets you save the graph to disk, send the graph to the printer, or copy the graph to the Windows Clipboard for placement in other Windows programs by way of the Paste Special operation.
While building the graph library, you learned how to declare and use enumerated constants to improve the readability of your Visual Basic code.
Finally, you used the new graph library to add three graphs to the CompanyMaster project.
Graph1.GraphType = graphBar3d
Graph1.GraphTitle = "Sales for October"
gphBlit gphCopy gphDraw
Assume that you are an analyst for your regional airport. The Manager of Operations wants information on passenger activity throughout the year. He is an extremely busy individual who does not understand database applications. In order to help him perform his job better, you have decided to create some graphs for him to review.
Perform the following steps in completing this project:
| Airline | Month | Passengers |
| ABC | 1 | 2562 |
| ABC | 2 | 4859 |
| ABC | 3 | 4235 |
| ABC | 4 | 4897 |
| ABC | 5 | 5623 |
| ABC | 6 | 4565 |
| ABC | 7 | 5466 |
| ABC | 8 | 2155 |
| ABC | 10 | 5454 |
| ABC | 11 | 5488 |
| ABC | 12 | 5456 |
| ABC | 9 | 5468 |
| LMN | 1 | 1956 |
| LMN | 2 | 2135 |
| LMN | 3 | 5221 |
| LMN | 4 | 2153 |
| LMN | 5 | 2154 |
| LMN | 6 | 5125 |
| LMN | 7 | 2135 |
| LMN | 8 | 5465 |
| LMN | 9 | 5555 |
| LMN | 10 | 2536 |
| LMN | 11 | 2153 |
| LMN | 12 | 2168 |
| XYZ | 1 | 10251 |
| XYZ | 2 | 12123 |
| XYZ | 3 | 10258 |
| XYZ | 4 | 12000 |
| XYZ | 5 | 21564 |
| XYZ | 6 | 21321 |
| XYZ | 7 | 14564 |
| XYZ | 8 | 12365 |
| XYZ | 9 | 21356 |
| XYZ | 10 | 21357 |
| XYZ | 11 | 21321 |
| XYZ | 12 | 12365 |
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