How to change the DataSource for DataGridVewComboBoxColumn at runtime in C#

Question

I am working on a project that reads in a hardware configuration xml file and parses and sorts its data by protocol type and channels for further modification that is displayed in a two column gridview. Column 1 holds the channel names as a DataGridViewTextBoxColumn while column 2 is setup as a DataGridViewComboBoxColumn where the user should be able to select an item from the dropdown list that was generated from a query from a SQL database (Channel-Type).

The SQL database table itself has couple columns that are as follows: Interface Channel-Type

The "Interface" column is used as a key to distinguish the "Channel-Type" if they are RS232, RS422, RS485, and so on.

As I populate the DataGridView, I sort it out to first run through all RS422 channel listing, followed by RS232 listings and so on. However, to do this I would need to be able to change the DataSource for the ComboBoxColumn to have different queries such as for the first it would be "SELECT Channel_Type FROM Table1 WHERE Interface='RS422'" while for the second one I would need to run "SELECT Channel_Type FROM Table1 WHERE Interface='RS232'"

So in the code I have the following:

private void scanner()
{
    //...code for parser that assembles a List<> ...

    ChannelTypeColumn.DataSource = Populate("SELECT Channel_Type FROM Table1 WHERE Interface='RS422'");
    ChannelTypeColumn.ValueMember = "Channel_Type";
    ChannelTypeColumn.DisplayMember = ChannelTypeColumn.ValueMember;

    for(int x = 0; x < ChannelRS422List.Count; x++)
    {
        RowDataBuffer[0] = ChannelRS422List.channel;
        dgv.Rows.Add(RowDataBuffer);
    }

    ChannelTypeColumn.DataSource = Populate("SELECT Channel_Type FROM Table1 WHERE Interface='RS232'");

    for(int x = 0; x < ChannelRS232List.Count; x++)
    {
        RowDataBuffer[0] = ChannelRS232List.channel;
        dgv.Rows.Add(RowDataBuffer);
    }
}

private DataTable Populate(string query)
{
    SqlCommand command = new SqlCommand(query, connection);
    SqlDataAdapter adapter = new SqlDataAdapter();
    adapter.SelectCommand = command;

    DataTable table = new DataTable();
    table.Locale = System.Globalization.CultureInfo.InvariantCulture;
    adapter.Fill(table);

    return table;
}

Unfortunately I am not sure how to change datasources correctly, since doing it with this methods only would show me a list of the items in the last datasource definition.

Any help and advise would be greatly appreciated!

Thanks!

Answer 1

After much trying, I finally found a method to do the problem. Instead of doing this by the column, I need to do it by the cell for the row I need it at.

private void scanner()
{
    //...code for parser that assembles a List<> ...

    for(int x = 0; x < ChannelRS422List.Count; x++)
    {
        RowDataBuffer[0] = ChannelRS422List.channel;
        dgv.Rows.Add(RowDataBuffer);
    }

    int rowCount = 0;
    for (int row = 0; row < dgv.Rows.Count; row++)
    {
        DataGridViewComboBoxCell cell = (DataGridViewComboBoxCell)(dgv.Rows[row].Cells[1]);
        cell.DataSource = Populate("SELECT Channel_Type FROM Table1 WHERE Interface='RS422'");
        cell.ValueMember = "Channel_Type";
        cell.DisplayMember = cell.ValueMember;
        rowCount = row+1;
    }

    for(int x = 0; x < ChannelRS232List.Count; x++)
    {
        RowDataBuffer[0] = ChannelRS232List.channel;
        dgv.Rows.Add(RowDataBuffer);
    }

    for (int row = rowCount; row < dgv.Rows.Count; row++)
    {
        DataGridViewComboBoxCell cell = (DataGridViewComboBoxCell)(dgv.Rows[row].Cells[1]);
        cell.DataSource = Populate("SELECT Channel_Type FROM Table1 WHERE Interface='RS232'");
        cell.ValueMember = "Channel_Type";
        cell.DisplayMember = cell.ValueMember;
        rowCount = row+1;
    }
}