错误消息“索引超出范围。 必须为非负数并且小于集合的大小。 参数名称：索引”

Question

I have a DataGridView . I want to add column 4 values. I wrote this code. But it shows above error on Total += Convert.ToDecimal(dgvSalesFooterAdd.Rows[i].Cells[4].Value); .

 decimal Total = 0;

 for (int i = 0; i < dgvSalesFooterAdd.Rows.Count; i++)
 {
      dgvSalesFooterAdd.Rows[i].Cells[4].Value = 
          Convert.ToDecimal(dgvSalesFooterAdd.Rows[i].Cells[3].Value) * 
          Convert.ToDecimal(dgvSalesFooterAdd.Rows[i].Cells[3].Value);

          Total += Convert.ToDecimal(dgvSalesFooterAdd.Rows[i].Cells[4].Value);
 }
 lblFinalTotalAdd.Text = Total.ToString();

Creating 5th column code:

            OleDbConnection con = new OleDbConnection(conn);
            con.Open();
            DataTable dtusers = new DataTable();
            OleDbCommand cmd = new OleDbCommand("Select Shorts,Code,Description,Percentage from SalesFields", con);
            OleDbDataAdapter da = new OleDbDataAdapter(cmd);
            da.Fill(dtusers);
            dgvSalesFooterAdd.DataSource = dtusers;
            dgvSalesFooterAdd.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
            dgvSalesFooterAdd.Columns[0].Name = "Shorts";
            dgvSalesFooterAdd.Columns[1].Name = "Code";
            dgvSalesFooterAdd.Columns[2].Name = "Description";
            dgvSalesFooterAdd.Columns[3].Name = "Percentage";
            dgvSalesFooterAdd.Columns[0].HeaderText = "Shorts";
            dgvSalesFooterAdd.Columns[1].HeaderText = "Code";
            dgvSalesFooterAdd.Columns[2].HeaderText = "Description";
            dgvSalesFooterAdd.Columns[3].HeaderText = "Percentage";
            DataGridViewColumn amount = new DataGridViewColumn();
            amount.HeaderText = "Amount";
            amount.Name = "Amount";
            amount.CellTemplate = new DataGridViewTextBoxCell();
            dgvSalesFooterAdd.Columns.Insert(4, amount);
            con.Close();

            con.Close();

Answer 1

C#'s arrays are zero-based. This means the first element is element 0. The 4th element is element 3.

You probably have only four columns, numbered 0 to 3.

Answer 2

Try this,

 decimal Total = 0;

 for (int i = 0; i < dgvSalesFooterAdd.Rows.Count; i++)
 {
      dgvSalesBodyAdd.Rows[i].Cells[3].Value = 
          Convert.ToDecimal(dgvSalesBodyAdd.Rows[i].Cells[2].Value) * 
          Convert.ToDecimal(dgvSalesBodyAdd.Rows[i].Cells[2].Value);

          Total += Convert.ToDecimal(dgvSalesFooterAdd.Rows[i].Cells[3].Value);
 }
 lblFinalTotalAdd.Text = Total.ToString();