Question

I finally solved one problem but now i have another. I found out how to get the name of the current field my selector is on, but now when I want to use an update command for it, they will not let me set a parameter. Heres some code…

    private void dgv_DataLookup_CellValueChanged(object sender, DataGridViewCellEventArgs e)
    {

        DialogResult dr;
        dr = MessageBox.Show("Are you sure you want to edit this field?", "Edit Cell", MessageBoxButtons.YesNo);

        if (dr == DialogResult.Yes)
        {
            string myCell = dgv_DataLookup.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString();
            string myIndex = dgv_DataLookup.CurrentCell.OwningRow.Cells[6].Value.ToString();
            string myColumn = dgv_DataLookup.CurrentCell.OwningColumn.HeaderCell.Value.ToString();
            myColumn.Trim();

            da.UpdateCommand = new OleDbCommand("UPDATE tbl_Orders SET @myColumn = @myCell WHERE oid = @myIndex", cs);
            da.UpdateCommand.Parameters.Add("@myColumn", OleDbType.VarChar).Value = myColumn;
            da.UpdateCommand.Parameters.Add("@myCell", OleDbType.VarChar).Value = myCell;
            da.UpdateCommand.Parameters.Add("@myIndex", OleDbType.Integer).Value = myIndex;

            cs_Execute("UPDATE");

        }
    }

when I change myColumn to the actual column, say itemNum, it works fine. However, the error was Cannot update ‘@myColumn’; field not updateable

I also had a message box showing me the value of myColumn and it was the correct value. I was just wondering if this was legal, seting a parameter to a parameter. If not, then I’ll just have to update all the rows. Thanks!

p.s. cd_Execute is just like cs.Open() da.UpdateCommand.ExecuteNonQuery() cs.Close()

Answer 1

You cannot have dynamic column names in parametrized queries. You will need to resort to dynamic SQL.

This will do what you want, though open to SQL Injection:

da.UpdateCommand = new OleDbCommand(string.Format("UPDATE tbl_Orders SET {0} = @myCell WHERE oid = @myIndex", myColumn), cs);