Question

Am new to this guys need your help! Am trying to multiply two field and the answer to that will be the result of my computed field. One field is from another table..

partial void SubTotal_Compute(ref decimal result)
{
    // Set result to the desired field value
       result = this.Quantity * this.Rate.PulaPerUnit;
}

Every-time i try to add a new record to the table i get a Null Reference exception

Answer 1

Rate is likely to be null. You should add a test for it before performing your calculation, e.g.

if (Rate != null)
{
    result = Quantity * Rate.PulaPerUnit;
}

You should probably ensure that Rate has been set before you call Subtotal_Compute.