C# SQL SUM value to a label

Question

I currently have a DataGridView which displays all the item. I would like to sum all the prices in the price column and then reflect the total in a label, \'TotalValueLabel\

Answer 1

DataTable is overkill for single value retrieval, besides your not even accessing the value correctly, better way is to use execute scalar:

var query = "SELECT SUM (Price) FROM Bill";
using (var cmd = new OleDbCommand(query, DBcon))
{
    TotalValueLabel.Text = cmd.ExecuteScalar().ToString();
}