Get Numeric Value from DataGridViewCell?

Question

I'm trying to retrieve numeric values from a DataGridView. So far, the only way I've found is to retrieve them as a string and convert them to numeric.

Convert.ToDouble(MyGrid.SelectedRows[0].Cells[0].Value.ToString());

There must be an easier way. The cell is originally populated from a DataSet with a numeric field value but since the DataGridViewCell object returns it as an object, I can't do a straight assignment. I must be missing something simple here.

Thanks.

Solution 1

I've actually just recently dealt with this problem and TryParse I think is your best bet with respect to robustness, but don't forget to check if the value in the Cell is null, if so TryParse will fail and throw up an error.

double d = 0;
if(grid[col,row].Value != null)
  double.TryParse(grid[col,row].Value.ToString(), out d);

I would also recommend avoiding a straight cast, unless you know absolutely what type you are converting and that there will, in fact, be a value there, it will probably at some point cause an error in your code.

Solution 2

With DataGridViewCell you can just cast the .Value to your known type; the following is a complete example that shows this happening (using double) from a DataTable (like your example). Additionally, Convert.To{blah}(...) and Convert.ChangeType(...) might be helpful.

using System.Data;
using System.Windows.Forms;
static class Program
{
    static void Main()
    {
        Application.EnableVisualStyles();
        DataTable table = new DataTable
        {
            Columns = {
                {"Foo", typeof(double)},
                {"Bar", typeof(string)}
            },
            Rows = {
                {123.45, "abc"},
                {678.90, "def"}
            }
        };
        Form form = new Form();
        DataGridView grid = new DataGridView {
            Dock = DockStyle.Fill, DataSource = table};
        form.Controls.Add(grid);
        grid.CurrentCellChanged += delegate
        {
            form.Text = string.Format("{0}: {1}",
                grid.CurrentCell.Value.GetType(),
                grid.CurrentCell.Value);

            if (grid.CurrentCell.Value is double)
            {
                double val = (double)grid.CurrentCell.Value;
                form.Text += " is a double: " + val;
            }
        };
        Application.Run(form);

    }
}

Solution 3

DataGridViewCell has ValueType property. You can use to do directly cast the value to that type without first converting it to string:

if(MyGrid.SelectedRows[0].Cells[0].ValueType!=null &&
   MyGrid.SelectedRows[0].Cells[0].ValueType == Double)
 return (Double)MyGrid.SelectedRows[0].Cells[0].Value;

Comments

[Marc Gravell]

It is the .Value you need to cast, not the DataGridViewCell itself.

[Marc Gravell]

Since the ValueType is a Type, you can't cast directly to the ValueType; however, you can check the Type is something you expect, though - but "is" might do just as well (nulls not withstanding).

[Leon Tayson]

yep, am so sleepy when i typed my reply. :)