How to get sum of datagrdview cells to the same datagridview

As mentioned, there are almost certainly better approaches. However, without a better understanding of your goal, its difficult to provide the best advice. At a minimum, I'd need to see how you are populating the DataGridView, the data types of the columns, the names of the columns included in the total, and the name of the column to receive the total. Again, assuming you are populating the grid via DataSource, you are probably calculating the sums at the source instead of on the grid itself.


The example I provided simply totals all columns (except the first), it assumes all columns have a value that can be converted to an integer, and it deposits the total in the first column.


Complete source for the test harness I threw together (very quickly) is...


using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private List<myobject> values = new List<myobject>
{
new MyObject { Col2 = 1, Col3 = 2, Col4 = 3},
new MyObject { Col2 = 4, Col3 = 5, Col4 = 6},
new MyObject { Col2 = 7, Col3 = 8, Col4 = 9},
new MyObject { Col2 = 10, Col3 = 11, Col4 = 12}
};

private void Form1_Load(object sender, EventArgs e)
{
dataGridView1.DataSource = values;
}

private class MyObject
{
public int Col1 { get; set; }

public int Col2 { get; set; }

public int Col3 { get; set; }

public int Col4 { get; set; }
}

private void button1_Click(object sender, EventArgs e)
{
foreach (DataGridViewRow row in dataGridView1.Rows)
{
int total = 0;
for (int index = 1; index < row.Cells.Count; index++)
total += Convert.ToInt32(row.Cells[index].Value);
row.Cells[0].Value = total;
}
}
}
}

Assuming you want to total all columns except the one named "Col1" and deposit the result there, the button-click code would change as follows:

int totalIndex = 0;
for (int index = 0; index < dataGridView1.Columns.Count; index++)
if (dataGridView1.Columns[index].Name == "Col1")
{
totalIndex = index;
break;
}

foreach (DataGridViewRow row in dataGridView1.Rows)
{
int total = 0;
for (int index = 0; index < row.Cells.Count; index++)
if (index != totalIndex)
total += Convert.ToInt32(row.Cells[index].Value);

row.Cells[totalIndex].Value = total;
}

However, I'll stress again that more information is needed for me (or anyone) to provide a good response. If this doesn't help you, you'll need to either mark the problem as not solved (if this allows it) or re-post. I may be unavailable for a while, so someone else may need to pick up where I left off.