How to Validate/Restrict DataGridView for Entering Only Number or Characters (if required)

1. Number Only Textbox with backspace

For that we can use EditingControlShowing Event of the datagridview

 Double click the EditingControlShowing event of the DataGridView

//Now we can create user defined event named as DataGrid_KeyPress

private void DataGrid_KeyPress(object sender, KeyPressEventArgs e)

{

    if ((e.KeyChar != (char)Keys.Back) && !char.IsDigit(e.KeyChar))

    {

        e.Handled = true;

    }   

}

//This code is to validate all columns

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)

{

   e.Control.KeyPress -= new KeyPressEventHandler(DataGrid_KeyPress);

   TextBox tb = e.Control as TextBox;

   if (tb != null)

   {

       tb.KeyPress += new KeyPressEventHandler(DataGrid_KeyPress);

   }

}

//This code is to validate particular columns

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)

{

     e.Control.KeyPress -= new KeyPressEventHandler(DataGrid_KeyPress);

     //Check columns whatever you required

     if (dataGridView1.CurrentCell.ColumnIndex == 2)

     {

         TextBox tb = e.Control as TextBox;

         if (tb != null)

         {

              tb.KeyPress += new KeyPressEventHandler(DataGrid_KeyPress);

         }

     }

     if (dataGridView1.CurrentCell.ColumnIndex == 3)

     {

         TextBox tb = e.Control as TextBox;

         if (tb != null)

         {

              tb.KeyPress += new KeyPressEventHandler(DataGrid_KeyPress);

         }

     }

}

2. Number Only Textbox with backspace and only one dot    

Then change the above code with this, balance all same

private void DataGrid_KeyPress(object sender, KeyPressEventArgs e)

{

    if ((e.KeyChar != (char)Keys.Back) && !char.IsDigit(e.KeyChar) && e.KeyChar != '.')

     {

        e.Handled = true;

     }

     //Here is the code that will allow one decimal point

     if (e.KeyChar == '.' && (sender as TextBox).Text.IndexOf('.') > -1)

     {

        e.Handled = true;

     }

}

3. If we want to add only one character and other number only means we can replace ‘.’(dot/point) with the special characters like A~Z or a~z or  ,;[]' " \ etc

Then change the above code with this, balance all same

private void DataGrid_KeyPress(object sender, KeyPressEventArgs e)

{

    if ((e.KeyChar != (char)Keys.Back) && !char.IsDigit(e.KeyChar) && e.KeyChar != 'c')

     {

        e.Handled = true;

     }

     //Here is the code that will allow one decimal point

     if (e.KeyChar == 'c' && (sender as TextBox).Text.IndexOf('c') > -1)

     {

        e.Handled = true;

     }

}