Question

This code works anywhere else.. form load, button click, etc. But when I add it to my tripsBindingSource_PositionChanged it says object reference not set to an instance of an object when its getting the selected row index. I’m assuming there is no selected row yet but why would it work at form load than? It is making my app bomb at run time. What can I do to fix this? Thanks!

private void tripsBindingSource_PositionChanged(object sender, EventArgs e)
{ 
    //get selected row index
    int index = this.dgvTripGrid.CurrentRow.Index;
    //get pk of selected row using index
    string cellValue = dgvTripGrid["pkTrips", index].Value.ToString();
    //change pk string to int
    int pKey = Int32.Parse(cellValue);
    ...
}

Answer 1

You have to check if the row is null first and then only do your load if it is not null

private void tripsBindingSource_PositionChanged(object sender, EventArgs e)
{ 
    // something like
    if(dgvTripGrid.CurrentRow != null)
    {
        //get selected row index
        int index = this.dgvTripGrid.CurrentRow.Index;
        //get pk of selected row using index
        string cellValue = dgvTripGrid["pkTrips", index].Value.ToString();
        //change pk string to int
        int pKey = Int32.Parse(cellValue);
        ...
    }
}