Can't Delete DataGridViewRow WIthout Exception

Question

I have a DataGridView with 3 columns that is bound to a DataTable.  The first DataGridView column is a DataGridViewLinkColumn that is clicked by the user to delete a row.  In my example below, if you left-click the cell that contains text "$200.00",
press the Delete key to clear the data, then left-click the "Remove" link on that same row you get a
NoNullAllowedException:  "Column 'Cost' does not allow nulls.".  I'm assuming this is because
Nothing or
DBNull.Value is pushed to the underlying DataRow field "Cost" which doesn't allow nulls.  If the user clicks "Remove" I need to remove the DataGridViewRow and underlying DataRow.  Any ideas how to get around this issue?
Public Class Form1
Private clmRemove As New DataGridViewLinkColumn
Private clmDescription As New DataGridViewTextBoxColumn
Private clmCost As New DataGridViewTextBoxColumn
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
' create underlying datatable
Dim dt As New DataTable
Dim remove As New DataColumn("Remove", GetType(String))
Dim description As New DataColumn("Description", GetType(String))
description.AllowDBNull = False
Dim cost As New DataColumn("Cost", GetType(Decimal))
cost.AllowDBNull = False
dt.Columns.AddRange({remove, description, cost})
dt.Rows.Add("Remove", "desc 1", 100D)
dt.Rows.Add("Remove", "desc 2", 200D)
' create datagridview
With Me.DataGridView1
clmRemove.AutoSizeMode = DataGridViewAutoSizeColumnMode.DisplayedCells
clmRemove.HeaderText = ""
clmRemove.DataPropertyName = remove.ColumnName
clmDescription.HeaderText = "Description"
clmDescription.DataPropertyName = description.ColumnName
clmDescription.DefaultCellStyle.WrapMode = DataGridViewTriState.True
clmCost.HeaderText = "Cost"
clmCost.DataPropertyName = cost.ColumnName
clmCost.DefaultCellStyle.Format = "c"
.Columns.AddRange(clmRemove, clmDescription, clmCost)
.AllowUserToAddRows = False
.AllowUserToDeleteRows = False
.RowHeadersVisible = False
.AutoGenerateColumns = False
.EditMode = DataGridViewEditMode.EditOnEnter
.SelectionMode = DataGridViewSelectionMode.CellSelect
.RowTemplate.Resizable = DataGridViewTriState.False
.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.AllCellsExceptHeaders
.DataSource = dt
End With
End Sub
Private Sub DataGridView1_CellContentClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
If e.ColumnIndex = Me.clmRemove.Index And e.RowIndex > Me.DataGridView1.TopLeftHeaderCell.RowIndex Then
Me.DataGridView1.Rows.RemoveAt(e.RowIndex)
'CType(CType(Me.DataGridView1.Rows(e.RowIndex).DataBoundItem, DataRowView).Row, dsQuoteData.LineItemCustomItemsRow).Delete()
End If
End Sub
End Class
Ryan

Answer 1

Hello,
The following might help in that it will prevent the null exception when a decimal value is missing
Public Class Form1
Private Sub Form1_Load() Handles MyBase.Load
Dim dt As New DataTable()
dt.Columns.Add("DecimalOne", GetType(Decimal))
dt.Columns.Add("DecimalTwo", GetType(Decimal))
dt.Rows.Add(1.23, 2.22)
dt.Rows.Add(93.23, 90.5)
dt.Rows.Add(9.56, 6.0)
DataGridView1.DataSource = dt
End Sub
Private Sub DataGridView1_CellValidating(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles DataGridView1.CellValidating
If DataGridView1.Item(e.ColumnIndex, e.RowIndex).IsInEditMode Then
Dim c As Control = DataGridView1.EditingControl
If DataGridView1.Columns(e.ColumnIndex).Name = "DecimalOne" Then
c.Text = NumberCleaner(c.Text)
End If
End If
End Sub
Function NumberCleaner(ByVal str As String) As String
Return System.Text.RegularExpressions.Regex.Replace(str, "[a-zA-Z\b\s-]", "")
End Function
Private Sub DataGridView1_DataError(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewDataErrorEventArgs) Handles DataGridView1.DataError
If e.ColumnIndex = 1 Then
If e.Exception.Message.Contains("not in a correct format") Then
MessageBox.Show("Only 0-9 and decimals are permitted")
End If
e.Cancel = False
End If
End Sub
End Class
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