Data Grid Customization

Public Class Form1
Inherits System.Windows.Forms.Form
Private MyDataSet As DataSet

#Region " Windows Form Designer generated code "

Public Sub New()
MyBase.New()

'This call is required by the Windows Form Designer.
InitializeComponent()

'Add any initialization after the InitializeComponent() call

End Sub

'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub

'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer

'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
Friend WithEvents DataGrid1 As MyDataGrid
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
Me.DataGrid1 = New MyDataGrid
CType(Me.DataGrid1, System.ComponentModel.ISupportInitialize).BeginInit()
Me.SuspendLayout()
'
'DataGrid1
'
Me.DataGrid1.DataMember = ""
Me.DataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText
Me.DataGrid1.Location = New System.Drawing.Point(8, 8)
Me.DataGrid1.Name = "DataGrid1"
Me.DataGrid1.Size = New System.Drawing.Size(520, 440)
Me.DataGrid1.TabIndex = 0
'
'Form1
'
Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
Me.ClientSize = New System.Drawing.Size(536, 454)
Me.Controls.Add(Me.DataGrid1)
Me.Name = "Form1"
Me.Text = "Form1"
CType(Me.DataGrid1, System.ComponentModel.ISupportInitialize).EndInit()
Me.ResumeLayout(False)

End Sub

#End Region

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Create Data Set
MyDataSet = New DataSet("MyDataSet")

Dim myTable As New DataTable("Customers")

Dim myColumn As New DataColumn("CustomerID")
myTable.Columns.Add(myColumn)

myColumn = New DataColumn("CustomerName")
myTable.Columns.Add(myColumn)

MyDataSet.Tables.Add(myTable)

Dim myRow As DataRow = myTable.NewRow()

myRow("CustomerID") = "100"
myRow("CustomerName") = "John Doe"
myTable.Rows.Add(myRow)

myRow = myTable.NewRow()

myRow("CustomerID") = "200"
myRow("CustomerName") = "Mary Lou"
myTable.Rows.Add(myRow)

'Bind Data Grid
DataGrid1.SetDataBinding(MyDataSet, "Customers")

'Add Custom DataTableStyle
Dim myTableStyle As New DataGridTableStyle
myTableStyle.MappingName = "Customers"

Dim myTextColumn As New MyDataGridTextBoxColumn
myTextColumn.MappingName = "CustomerID"
myTextColumn.HeaderText = "Customer ID"
myTextColumn.Width = 100

myTableStyle.GridColumnStyles.Add(myTextColumn)

myTextColumn = New MyDataGridTextBoxColumn
myTextColumn.MappingName = "CustomerName"
myTextColumn.HeaderText = "Customer Name"
myTextColumn.Width = 200

myTableStyle.GridColumnStyles.Add(myTextColumn)

DataGrid1.TableStyles.Add(myTableStyle)

End Sub
End Class

Public Class MyDataGrid
Inherits DataGrid
Public blnEdit As Boolean = False

Private Sub MyDataGrid_CurrentCellChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.CurrentCellChanged
blnEdit = False
End Sub

Private Sub MyDataGrid_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown
' Use the HitTest method to get a HitTestInfo object.
Dim hi As DataGrid.HitTestInfo
Dim grid As DataGrid = CType(sender, DataGrid)
hi = grid.HitTest(e.X, e.Y)
' Test if the clicked area was a cell.
If hi.Type = DataGrid.HitTestType.Cell Then
blnEdit = True
End If
End Sub

Protected Overrides Function ProcessCmdKey(ByRef msg As System.Windows.Forms.Message, ByVal keyData As System.Windows.Forms.Keys) As Boolean
If msg.WParam.ToInt32() = CInt(Keys.Enter) Then
SendKeys.Send("{Tab}")
Return True
End If

blnEdit = True

Return MyBase.ProcessCmdKey(msg, keyData)

End Function 'ProcessCmdKey

Private Sub MyDataGrid_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown
blnEdit = True
End Sub
End Class

Public Class MyDataGridTextBoxColumn
Inherits DataGridTextBoxColumn

Protected Overloads Overrides Sub Edit(ByVal source As System.Windows.Forms.CurrencyManager, ByVal rowNum As Integer, ByVal bounds As System.Drawing.Rectangle, ByVal [readOnly] As Boolean, ByVal instantText As String, ByVal cellIsVisible As Boolean)
If Not CType(Me.DataGridTableStyle.DataGrid, MyDataGrid).blnEdit Then
Me.HideEditBox()
Else
MyBase.Edit(source, rowNum, bounds, [readOnly], instantText, cellIsVisible)
End If
End Sub

Protected Overloads Overrides Sub Paint(ByVal g As System.Drawing.Graphics, ByVal bounds As System.Drawing.Rectangle, ByVal source As System.Windows.Forms.CurrencyManager, ByVal rowNum As Integer, ByVal backBrush As System.Drawing.Brush, ByVal foreBrush As System.Drawing.Brush, ByVal alignToRight As Boolean)
If DataGridTableStyle.DataGrid.CurrentRowIndex = rowNum _
And DataGridTableStyle.DataGrid.CurrentCell.ColumnNumber = DataGridTableStyle.GridColumnStyles.IndexOf(Me) Then
backBrush = New SolidBrush(Color.Red)
End If

MyBase.Paint(g, bounds, source, rowNum, backBrush, foreBrush, alignToRight)
End Sub
End Class

codefund.com at 2007-9-8 >

in your code you set the blnEdit bit to true when processing the key messages and the mouse messages but you reset it to false in the handler for current cell changed event. then, when your column gets the edit mode the data grid::blnEdit is false so no editing happens.

I suggest that you don't use the blnEdit bit at all: in the DataGridColumn::Edit method simply put your text box on top of the grid.

codefund.com at 2007-9-8 >