Question

I’m trying in RowDataBound event to get a value from dataTable for the current editing row:
Here’s my code:

string KK = (string)DataBinder.Eval(e.Row.DataItem, "Name");
if ( KK == "John" )
{
//execute code
}

ERROR : Unable to cast object of type ‘System.DBNull’ to type ‘System.String’. at the first line ( the one with String KK…)

How can I fix that?

Answer 1

Use DataItem of the GridViewRow instead of DataBinder.Eval to get the underlying datasource:

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow && e.Row.RowState == DataControlRowState.Edit))
    {
        DataRow row = ((DataRowView)e.Row.DataItem).Row;
        String name = row.Field<String>("Name");
        // String is a reference type, so you just need to compare with null
        if(name != null){/* do something */}
    }
}

The Field extension method also supports nullable types.