Q149092: HOWTO: Add Records and Edit Data in a DBGrid Cell
Article: Q149092
Product(s): Microsoft Visual Basic for Windows
Version(s):
Operating System(s):
Keyword(s): kbcode kbCtrl kbVBp400
Last Modified: 11-JAN-2001
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The information in this article applies to:
- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0
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SUMMARY
=======
This article describes how to programmatically edit the data and add new records
to a DBGrid control. You can change the contents of a cell and those changes
will appear on the screen, but they are not written to the data source bound to
the DBGrid control. To write these changes to the data source, you must instead
edit the underlying recordset.
MORE INFORMATION
================
The following example creates a simple database containing one table with four
fields and five records. Each record is a number in the field. The database is
going to be the data source.
When you click on a cell, the data in that cell is shown in a TextBox. When you
change the contents of that cell, the changes are shown on the DBGrid control.
However, when you execute the UpdateControls method through a command button,
the changes disappear from the cell, indicating the data source was not
updated.
You must click the Update Recordset button when you make your changes in the
TextBox to ensure that the changes are written to the data source. The Update
Recordset button updates the underlying recordset of the Data control. Since the
DBGrid control is bound to the Data control, the changes appear in the DBGrid
control.
Creating the Sample Application
-------------------------------
The following sample application demonstrates how to edit the contents of a
DBGrid cell:
1. Start Visual Basic. Once it is running, on the File menu, click New Project.
Add a Data control, a DBGrid control, a TextBox, and three Command buttons.
Set the following properties for each control:
Control Default Name Property Value
-----------------------------------------------------
DBGrid DBGrid1 DataSource Data1
2. Copy the following code sample to the Form1 code window:
Option Explicit
Dim rs1 As Recordset
Dim db As Database
Dim td As TableDef
Dim fl As Field
Dim igRow As Integer, igColumn As Integer
Dim iFields As Integer, iRecords As Integer
Dim vargBookmark As Variant
Private Sub Command1_Click()
' The Create Database button: By clicking this button, you create
' a database with four fields and five records.
Set db = CreateDatabase("C:\test.mdb", dbLangGeneral)
Set td = db.CreateTableDef("Table1")
' After you create the database, you need to add fields to it.
For iFields = 1 To 4 ' The last number can be changed to the
' number of fields you want in the database.
Set fl = td.CreateField("Field " & CStr(iFields), dbText)
td.Fields.Append fl
Next iFields
db.TableDefs.Append td
' Now that you have added fields to the database, you need to add
' some records through a recordset.
Set rs1 = db.OpenRecordset("Table1", dbOpenTable)
For iRecords = 1 To 5 'For each row
rs1.AddNew 'Add a new record
For iFields = 1 To 4 ' For each field in the record, add
rs1("Field " & CStr(iFields)) = CStr(iFields) ' a number.
Next iFields
rs1.Update
Next iRecords
' Close both the recordset and database.
rs1.Close
db.Close
' Populate the DBGrid control with the contents of the Recordset.
Set db = OpenDatabase("C:\test.mdb")
Set rs1 = db.OpenRecordset("Select * from Table1")
Set Data1.Recordset = rs1
Command1.Visible = False
Command2.Visible = True
Command4.Visible = True
End Sub
Private Sub Command2_Click()
' The Update Database button: By clicking this button, you save
' the contents of the text box to the database. Since the contents
' of the recordset are being modified, the contents are saved to
' the database after you execute the Update method.
Data1.Recordset.Edit
Data1.Recordset.Fields(igColumn) = Text1.Text
Data1.Recordset.Update
End Sub
Private Sub Command3_Click()
' The Update DBGrid button: By clicking this button, you execute
' the UpdateControls method on the Data control to demonstrate
' that changing the cell in a bound DBGrid control does not save
' the new information to the database. To save these changes, you
' must modify the underlying recordset from the Data control.
Data1.UpdateControls
End Sub
Private Sub Command4_Click()
' The Add New Record button: By clicking this button, you add new
' records to the recordset. Use the following code to add a new
' record to the DBGrid control.
' Set DBGrid and Data Control Properties to allow new records to
' be added.
DBGrid1.AllowAddNew = True
Data1.EOFAction = vbAddNew
Data1.Recordset.MoveLast
Data1.Recordset.MoveNext
DBGrid1.Row = DBGrid1.VisibleRows - 1
Data1.Recordset.AddNew
For iFields = 1 To 4 ' For each field in the record,
' add the contents of the text box.
Data1.Recordset("Field " & CStr(iFields)) = Text1.Text
Next iFields
Data1.Recordset.Update
End Sub
Private Sub DBGrid1_Change()
Command3.Visible = True
End Sub
Private Sub DBGrid1_MouseUp(Button As Integer, Shift As Integer, _
X As Single, Y As Single)
Command2.Visible = True
igColumn = DBGrid1.ColContaining(X)
igRow = DBGrid1.RowContaining(Y)
vargBookmark = DBGrid1.RowBookmark(igRow)
Text1.Text = DBGrid1.Columns(igColumn).CellValue(vargBookmark)
End Sub
Private Sub Form_Load()
Command1.Visible = False
Command2.Visible = False
Command3.Visible = False
Command4.Visible = False
Command1.Caption = "Create Database"
Command2.Caption = "Update Database"
Command3.Caption = "Update DBGrid"
Command4.Caption = "Add New Record"
' If the database does not exist, show the Create Database button.
If Dir("C:\test.mdb") = "" Then
Command1.Visible = True
Else
' Open an existing database.
Set db = OpenDatabase("C:\test.mdb")
Set rs1 = db.OpenRecordset("Select * from Table1")
Set Data1.Recordset = rs1
Command4.Visible = True
End If
End Sub
Private Sub Text1_Change()
Command2.Visible = True
End Sub
Running the Sample Application
------------------------------
1. On the Run menu, click Start, or press F5.
2. Click on a cell on the DBGrid control and change the contents of that cell.
Click the Update DBGrid button. Note that your changes disappear from the
DBGrid. Clicking on a blank area on the DBGrid control gives error 6148 -
Invalid row number.
3. Click on a cell. Note that the contents of the cell appear on the TextBox.
Change the contents of the TextBox and then click the Update Recordset
button. Note that your changes now appear on the DBGrid control.
4. Click the Add New Records button to add a new record to the DBGrid control.
The contents of the text box will be added as a new record.
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Keywords : kbcode kbCtrl kbVBp400
Technology : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Issue type : kbhowto
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