C# int and ushort computation

Emma Emma

Hi,

I have one problem now:
I need to get the last row first column cell value from datagridview. Then minus 100 to get the finally value. Then convert this value to ushort as a parameter to one function.

Here is my code:

int line = dataGridView.Rows.Count-1;
int min = 100;
int minu=Convert.ToInt16(dataGridView.Rows[line].Cells[0].Value.ToString()) - min;

ushort max = (ushort)minu;

but I get the error said that:
Object reference not set to an instance of an object. in this line :
int minu=Convert.ToInt16(dataGridView.Rows[line].Cells[0].Value.ToString()) - min;

I do not understand what is wrong. I read a lot about int and ushort...but still do not understand..
anyone help me...

2 Replies

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Vulpes13y ago
Accepted answer
Try:

int line = dataGridView.Rows.Count-1;
int min = 100;
int minu = 0; // say
object obj = dataGridView.Rows[line].Cells[0].Value;
if (obj != null) // make sure there's a value in that cell
{
minu = Math.Max(Convert.ToInt32(obj.ToString()) - min, 0); // make sure its non-negative
}

ushort max = (ushort)minu;
Emma Emma13y ago
Hi Vulpes, it wors now...Thanks soooo muchhh!!