Difference operation in datagridview

Question

hello,

how can i make a difference between column 3 and 2, and the result to be writen to column 4 ?

i tried with :

int n = dataGridView1.Rows.Add();
dataGridView1.Rows[n].Cells[3].Value = (int)dataGridView1.Rows[n].Cells[2].Value - (int)dataGridView1.Rows[n].Cells[1].Value;

but no result.

any idea?

ty

Sam Hobbs · Answer

I think we should get clarification before answering. I assume that if the rows are empty as Vulpes suggests then that would be obvious. I assume that the question is not clear and data is being put into the DataGridView after rows are added. If so then the cause of the problem is not shown here. Adding logic to iterate through the rows might not be necessary. If I could, I would determine why it is not working instead of guessing. As best as I understand the question, this is for a Windows Forms DataGridView. Evidently Senthilkumar thought this is for an ASP.Net Gridview. The DataGridView has a RowsAdded event that could be used. The following is sample code for that. private void dataGridView1_RowsAdded( object sender, DataGridViewRowsAddedEventArgs e) { for ( int i = e.RowIndex; i { int v1=0, v2=0; int .TryParse(dataGridView1.Rows[i].Cells[0].Value.ToString(), out v1); int .TryParse(dataGridView1.Rows[i].Cells[1].Value.ToString(), out v2); dataGridView1.Rows[i].Cells[2].Value = v1 + v2; } }

Senthilkumar · Answer

If those two columns are editable then you need to iterate the grid and calculate the value. If it it not then write the rowdatabound event. You have include this in your grid. [OnRowDataBound="GridView1_RowDataBound"] In the server side, you have to write the following event and code. protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.DataRow) { int col1 = Convert.ToInt32(e.Row.Cells[1].Text.ToString()); int col2 = Convert.ToInt32(e.Row.Cells[2].Text.ToString()); int diff = col1 = col2; e.Row.Cells[3].Text = diff.ToString(); } } Hope this will help you...

Vulpes · Answer

You appear to be performing these calculations on a new row (Rows.Add returns the index of the new row) which will be empty as no data has yet been added to it. You therefore need to perform the calculation on the existing rows: for(int i = 0; i { DataGridViewRow row = dataGridView1.Rows[i]; if (row.IsNewRow) break; row.Cells[3].Value = (int)row.Cells[2].Value - (int)row.Cells[1].Value; }