Can someone tell me / post some codes here on how could I validate my datagridview? I mean, a certain column on my datagridview should accept integers only, otherwise, it will return a messagebox. Kindly include on which event it should be posted. Thank you very much. God Bless. :D

Hi!

Check this:

Private Sub DataGridView1_CellEndEdit(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellEndEdit
        If (e.ColumnIndex = 0) Then   ' Checking numeric value for Column1 only
            Dim value As String = DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value.ToString()
            For Each c As Char In value
                If Not Char.IsDigit(c) Then
                    MessageBox.Show("Please enter numeric value.")
                    DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = String.Empty
                    Exit Sub
                End If
            Next
        End If
    End Sub

Another Alternative using same event:

Private Sub DataGridView1_CellEndEdit(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellEndEdit
        If (e.ColumnIndex = 0) Then   ' Checking numeric value for Column1 only
            Dim value As String = DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value.ToString()
            If Not Information.IsNumeric(value) Then
                MessageBox.Show("Please enter numeric value.")
                DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = String.Empty
                Exit Sub
            End If
        End If
    End Sub

Thank you very much. I'm gonna try those. :D

It's great but there are some errors. I'm so sorry. The message box only appears when I leave the column blank.

Hmm... glad to see that your problem "Solved". :)
Please close thread, so that other expert may avoid to comment on it.

I'm so sorry but I'm having problems. The column I want to validate is column 4. since the codes is (e.ColumnIndex = 1) there are some errors when I change it to (e.ColumnIndex = 4). :(

You should write:
e.ColumnIndex = 3

since index is zero-based.

If this don't help please post the error message.

Actually, I hid the index 0 of my datagrid to prevent users from editing them. So, now my index is 1. when I changed e.columnindex = 3 it worked for my column 3(Middle Name) . But when I used for e.columnindex = 4 for my column 4 (Contact Number where I need it) it posted errors, there some exception reports.

Hi!

This line:

If (e.ColumnIndex = 1) Then

works for the Visible columns so no need to take care of the InVisible columns. Also in this line:

Dim value As String = DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value.ToString()

e.RowIndex and e.ColumnIndex will get value from the visible columns of the DataGridView so I don't think so that the error should raise if value provided correctly.

Thanks. I am thinking of that as well. There is no error regarding about the program, I guess. Errors like System.FormatException: Input string was not in correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer&number, NumberFormatInfo info, Boolean parseDecimal) showed. What I am thinking now is that column 4 (Contact Number is declared as integer in mysql and the rest are varchar and it works on other columns except contact number).

I'm so sorry if I have a lot of questions. Is it possible if the input is like Dim value as integer? Like in here: Dim value As String = DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value.ToString() ---> I think the DB reads it as string instead of integer when contact number column is declared int in sql.

".Value" returns "object" datatype. so we can cast it into its appropriate type.
I found this error on PrimaryKey Column. Could you please check by adding this code:

Private Sub DataGridView1_DataError(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewDataErrorEventArgs) Handles DataGridView1.DataError
        MessageBox.Show("Please enter a numeric value")
    End Sub

This worked for me without any error:

Private Sub DataGridView1_CellEndEdit(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellEndEdit
        If (e.ColumnIndex = 1) Then   ' Checking numeric value for Column1 only
            If DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value <> Nothing Then
                Dim value As String = DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value.ToString()
                If Not Information.IsNumeric(value) Then
                    MessageBox.Show("Please enter numeric value.")
                    DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = String.Empty
                    Exit Sub
                End If
            End If
        End If
    End Sub

    Private Sub DataGridView1_DataError(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewDataErrorEventArgs) Handles DataGridView1.DataError
        MessageBox.Show("Please enter a numeric value")
    End Sub

Thank you very much! This worked on me flawlessly. I tried DataError before because that's what the error suggest me to do but still I didn't get it. I'm so sorry for disturbing you. But thank you very much, you helped me a lot. May God Bless you. :D

I am here to provide you help, so nothing disturbed me.
If you think that your problem solved, close the thread.

Again, thank you very much. I hope if I have to ask regarding programs again, you'd be helping me still. Continue helping others. God Bless us all. :D

The respected DaniWeb !
Thanks big!
It is very a pity, that I do not know English, I write by means of the translator.
Valeri