As Charges is not included within your Table columns so you will get this error.
A field or property with the name charges was not found on the selected data source
What you can do is if you want to add a custom column to your GridView you need to add extra boundfield Column to your GridView
This is RowDataBoundEevent:
protected void GridView_OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
bool isRead = Convert.ToBoolean((e.Row.Cells[1].FindControl("lblIsRead") as Label).Text);
e.Row.Cells[3].Text = isRead == true ? "true" : "false";
}
}
I am setting Cells[3].Text value based on Cells[1].Text.