protected void GridView1_OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
decimal mycolumn= 7.50;
TextBox txtHrsSpentColumn = (TextBox)e.Row.FindControl("TxtHoursSpent");
txtHrsSpentColumn.Text = mycolumn.ToString();
}
}
Please check if this is what you need.
if the value of mycolumn variable is coming from a control change it to
decimal mycolumn = Convert.ToDecimal(TextBox.Text);