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Juan Manuel Palacios
Asked: 2020-12-06 11:38:42 +0800 CST 2020-12-06 11:38:42 +0800 CST

How can I validate if the value of a cell of a DataGridView is Null?

  • 772

I'm trying to validate the content of a cell inside a DataGridView when the CellValidated event is fired and I've seen different ways to deal with the problem, but I can't get around the Null error when running the application.

The error I get is NullReferenceException was Unhandledand that the reference is not set to an instance of an object. This error happens when I leave the cell blank to move to another cell, that If's when it drops. It should be noted that I am using the Gridfor a direct entry.

What I'm thinking of including is a try..catchto bypass the problem, but I think that's not the best option.

The code of the event that I am using is the following:

private void dgvProductosPropios_CellValidated(object sender, DataGridViewCellEventArgs e)
{
    if (dgvProductosPropios.Columns[e.ColumnIndex].Name == "_marcaCodigo")
    {
        if (dgvProductosPropios.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString() == String.Empty) 
            cMarca = dgvProductosPropios.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString();
        else
            cMarca = "";
    }
}
c#

1 Answers

  1. Best Answer

    Try validating the cell first:

    private void dgvProductosPropios_CellValidated(object sender, DataGridViewCellEventArgs e)
        {
          if (!CeldaEsNull(dgvProductosPropios.Rows[e.RowIndex].Cells[e.ColumnIndex]))
           {
            if (dgvProductosPropios.Columns[e.ColumnIndex].Name == "_marcaCodigo")
            {
                if (dgvProductosPropios.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString() == String.Empty) 
                    cMarca = dgvProductosPropios.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString();
                else
                    cMarca = "";
            }
           }
        }

private bool CeldaEsNull(DataGridViewCell celda)
{
 return celda.Value == null || celda.Value == DBNull.Value || String.IsNullOrWhiteSpace(celda.Value.ToString());
}
    • 3