Validate Windows Form DataGridView cell values using C# and VB.Net

Hi smile,

Refer below sample.

Code

C#

private void Form1_Load(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[] { new DataColumn("AdmissionNo", typeof(string)), new DataColumn("Name", typeof(string)) });
    dt.Rows.Add("R-00001", "Mudassar");
    dt.Rows.Add("R-00002", "John");
    dt.Rows.Add("R-00003", "Robert");
    dGVMarks.DataSource = dt;
    DataGridViewCheckBoxColumn checkBoxColumn = new DataGridViewCheckBoxColumn();
    checkBoxColumn.HeaderText = "";
    checkBoxColumn.Width = 30;
    checkBoxColumn.Name = "checkBoxColumn";
    dGVMarks.Columns.Insert(0, checkBoxColumn);

    DataGridViewTextBoxColumn txtMax = new DataGridViewTextBoxColumn();
    txtMax.HeaderText = "Max";
    txtMax.Name = "Max";
    txtMax.Width = 95;
    dGVMarks.Columns.Insert(3, txtMax);

    DataGridViewTextBoxColumn txtMark = new DataGridViewTextBoxColumn();
    txtMark.HeaderText = "Mark";
    txtMark.Name = "Mark";
    txtMark.Width = 75;
    dGVMarks.Columns.Insert(4, txtMark);
}

private void dGVMarks_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)
{
    if (e.ColumnIndex > 1)
    {
        if (!string.IsNullOrEmpty(dGVMarks.Rows[e.RowIndex].Cells["Mark"].EditedFormattedValue.ToString()) && !string.IsNullOrEmpty(dGVMarks.Rows[e.RowIndex].Cells["Max"].EditedFormattedValue.ToString()))
        {
            int maxMark = Convert.ToInt16(dGVMarks.Rows[e.RowIndex].Cells["Max"].EditedFormattedValue);
            int obtainMark = Convert.ToInt16(dGVMarks.Rows[e.RowIndex].Cells["Mark"].EditedFormattedValue);
            if (obtainMark > maxMark)
            {
                MessageBox.Show("obtained marks should be less than max Marks");
            }
        }
    }
}

VB.Net

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn() {New DataColumn("AdmissionNo", GetType(String)), New DataColumn("Name", GetType(String))})
    dt.Rows.Add("R-00001", "Mudassar")
    dt.Rows.Add("R-00002", "John")
    dt.Rows.Add("R-00003", "Robert")
    dGVMarks.DataSource = dt
    Dim checkBoxColumn As DataGridViewCheckBoxColumn = New DataGridViewCheckBoxColumn()
    checkBoxColumn.HeaderText = ""
    checkBoxColumn.Width = 30
    checkBoxColumn.Name = "checkBoxColumn"
    dGVMarks.Columns.Insert(0, checkBoxColumn)
    Dim txtMax As DataGridViewTextBoxColumn = New DataGridViewTextBoxColumn()
    txtMax.HeaderText = "Max"
    txtMax.Name = "Max"
    txtMax.Width = 95
    dGVMarks.Columns.Insert(3, txtMax)
    Dim txtMark As DataGridViewTextBoxColumn = New DataGridViewTextBoxColumn()
    txtMark.HeaderText = "Mark"
    txtMark.Name = "Mark"
    txtMark.Width = 75
    dGVMarks.Columns.Insert(4, txtMark)
End Sub

Private Sub dGVMarks_CellValidating(ByVal sender As Object, ByVal e As DataGridViewCellValidatingEventArgs) Handles dGVMarks.CellValidating
    If e.ColumnIndex > 1 Then

        If Not String.IsNullOrEmpty(dGVMarks.Rows(e.RowIndex).Cells("Mark").EditedFormattedValue.ToString()) AndAlso Not String.IsNullOrEmpty(dGVMarks.Rows(e.RowIndex).Cells("Max").EditedFormattedValue.ToString()) Then
            Dim maxMark As Integer = Convert.ToInt16(dGVMarks.Rows(e.RowIndex).Cells("Max").EditedFormattedValue)
            Dim obtainMark As Integer = Convert.ToInt16(dGVMarks.Rows(e.RowIndex).Cells("Mark").EditedFormattedValue)

            If obtainMark > maxMark Then
                MessageBox.Show("obtained marks should be less than max Marks")
            End If
        End If
    End If
End Sub

Screenshot