DataGrid's Cell with DataGridTextBox's Change event

Hi to all,

Here is a problem with my DataGrid.

Problem 1:
How to prevent the user to add a new row in DataGrid and allow him to modify existing rows ?

Problem 2:
I want to update value of one DataGrid Cell based on other which is going edited by user.

I create a DataSet (without datasource) with 5 columns : ICode, Name,Qty,Rate and Amount.

All of these columns are defined with my custom DataTableStyle using my custom

DataGridTextBox (FormattableTextBoxColumn class) column. This class can raise event when

FormatableTextBox column value changed (DataGrid.TableStyle(0).C .TextBox_Changed event)

every time.

Now I want to update qty, I want Amount should update automatically. It is not happening.


The Form1 class's code and FormattableTextBoxColumn class's code is like :
(The entire project code is also as an attachment in TestGrid.Zip file)

Form1 Class

VB Code:

Public Class Form1
    Inherits System.Windows.Forms.Form
 
' Here was Form Generated Code
 
    Dim myDataSet As New DataSet()
    Dim myDataTable As New DataTable("Table1")
    Private OldRow As Integer
    Private OldCol As Integer
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) 
 
Handles MyBase.Load
        Dim tableStyle As New DataGridTableStyle()
        tableStyle.MappingName = "Table1"
 
        Dim column As New FormattableTextBoxColumn()
        column.MappingName = "ICode"
        column.HeaderText = "ICode"
        column.Width = 60
        tableStyle.GridColumnStyles.Add(column)
 
        column = New FormattableTextBoxColumn()
        column.MappingName = "Name"
        column.HeaderText = "Name"
        column.Width = 140
        tableStyle.GridColumnStyles.Add(column)
 
        column = New FormattableTextBoxColumn()
        column.MappingName = "Qty"
        column.HeaderText = "Qty"
        column.Width = 40
        AddHandler column.CellTextBoxChanged, AddressOf QtyTextBoxChanged
        tableStyle.GridColumnStyles.Add(column)
 
        column = New FormattableTextBoxColumn()
        column.MappingName = "Rate"
        column.HeaderText = "Rate"
        column.Width = 40
        tableStyle.GridColumnStyles.Add(column)
 
        column = New FormattableTextBoxColumn()
        column.MappingName = "Amount"
        column.HeaderText = "Amount"
        column.Width = 80
        tableStyle.GridColumnStyles.Add(column)
        Me.DataGrid1.TableStyles.Add(tableStyle)
 
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) 
 
Handles Button1.Click
        Dim datColumn As New DataColumn("ICode", System.Type.GetType("System.Int16"))
        myDataTable.Columns.Add(datColumn)
        datColumn = New DataColumn("Name", System.Type.GetType("System.String"))
        myDataTable.Columns.Add(datColumn)
        datColumn = New DataColumn("Qty", System.Type.GetType("System.Int16"))
        myDataTable.Columns.Add(datColumn)
        datColumn = New DataColumn("Rate", System.Type.GetType("System.Decimal"))
        myDataTable.Columns.Add(datColumn)
        datColumn = New DataColumn("Amount", System.Type.GetType("System.Decimal"))
        myDataTable.Columns.Add(datColumn)
 
        myDataSet.Tables.Add(myDataTable)
 
        AddMenuItem(101, "Coffee", 4, 25)
        AddMenuItem(102, "Tamato Soup", 2, 20)
        AddMenuItem(103, "Pizza", 2, 80)
        AddMenuItem(104, "Ice Cream", 8, 35)
        AddMenuItem(105, "Cold Drink", 2, 15)
 
        Me.DataGrid1.SetDataBinding(myDataSet, "Table1")
    End Sub
 
    Private Sub AddMenuItem(ByVal pICode As Int16, ByVal pIName As String, ByVal pQty As 
 
Int16, ByVal pRate As Decimal)
        Dim tt As DataTable
        tt = myDataTable
        Dim dr As DataRow = tt.NewRow
        dr(0) = pICode
        dr(1) = pIName
        dr(2) = pQty
        dr(3) = pRate
        dr(4) = pQty * pRate
        myDataTable.Rows.Add(dr)
    End Sub
 
    Private Sub QtyTextBoxChanged(ByVal sender As Object, ByVal e As System.EventArgs)
        If Not (OldRow = Me.DataGrid1.CurrentCell.RowNumber And OldCol = 
 
Me.DataGrid1.CurrentCell.ColumnNumber) Then
            OldRow = Me.DataGrid1.CurrentCell.RowNumber
            OldCol = Me.DataGrid1.CurrentCell.ColumnNumber
            Exit Sub
        Else
            With Me.DataGrid1
                .Item(.CurrentRowIndex, 4) = Val(.Item(.CurrentRowIndex, 2)) * 
 
Val(.Item(.CurrentRowIndex, 3))
            End With
            MsgBox("Event Fired")
        End If
    End Sub
 
End Class

FormattableTextBoxColumn class:

VB Code:

Public Class FormattableTextBoxColumn
    Inherits DataGridTextBoxColumn
 
    Public Event CellTextBoxChanged As System.EventHandler
 
    Public Sub New()
        MyBase.New()
        AddHandler Me.TextBox.TextChanged, New System.EventHandler(AddressOf 
 
TxtBoxChanged)
    End Sub
 
    Private Sub TxtBoxChanged(ByVal sender As Object, ByVal e As System.EventArgs)
        RaiseEvent CellTextBoxChanged(Me, e)
    End Sub
End Class

The entire project is attached.

Thanks in advance

Quote:

---

Originally posted by parminder
Problem 1:
How to prevent the user to add a new row in DataGrid and allow him to modify existing rows ?

---

Bind it to a dataview that its allownew is set to false.

And for the second problem. I wouldnt catch the textbox change event of datagrid, instead i will add this line to the code and let alone that textchange event.

VB Code:

datColumn = New DataColumn("Amount", System.Type.GetType("System.Decimal"))
[b]datColumn.Expression = "Rate * Qty"[/b]
myDataTable.Columns.Add(datColumn)

And the reason your code does not work is that while you are changing the text in the datagrid text, the underlying datasource is not updated yet and its value is still the same untill you move away from that column. So using your code you should move to another column, then back to this column and now if you change it. the 'Amount' column will be updated by the previous 'Qty'.

Thanks Lutanic3,

your alternative solution is good. I also found the other alternative solution. I changed the code of QtyTextBoxChanged procedure as follows (but still your code is good)

VB Code:

Private Sub QtyTextBoxChanged(ByVal sender As Object, ByVal e As System.EventArgs)
        Dim ftb As FormattableTextBoxColumn
        ftb = sender
        If Not (OldRow = Me.DataGrid1.CurrentCell.RowNumber And OldCol = Me.DataGrid1.CurrentCell.ColumnNumber) Then
            OldRow = Me.DataGrid1.CurrentCell.RowNumber
            OldCol = Me.DataGrid1.CurrentCell.ColumnNumber
            Exit Sub
        Else
            With Me.DataGrid1
                If Len(Trim(ftb.TextBox.Text)) = 0 Then
                    Exit Sub
                End If
                Me.DataGrid1.EndEdit(Me.DataGrid1.TableStyles(0).GridColumnStyles("Qty"), Me.DataGrid1.CurrentRowIndex, False)
                .Item(.CurrentRowIndex, 4) = Val(.Item(.CurrentRowIndex, 2)) * Val(.Item(.CurrentRowIndex, 3))
                Me.DataGrid1.BeginEdit(Me.DataGrid1.TableStyles(0).GridColumnStyles("Qty"), Me.DataGrid1.CurrentRowIndex)
                ftb.TextBox.SelectionStart = Len(Trim(ftb.TextBox.Text))
                ftb.TextBox.SelectionLength = 0
            End With
        End If
    End Sub

I will try your solution for problem 1.

Here is another problem .

When I design KeyPress or KeyDown events of FormattedTextBox, the event is not fired when I press "Enter" (and some special keys like leftarrow,rightarrow). Other Alfa and Numeric keys works fine. How to handle this problem.

I want, when user press Enter, Rightside cell in same row should make active (or any specific)

Thanks