如何从我的DataGridView获取每个组合框的所有值并将其添加到DataTable？

Question

I added a ComboBox to my DataGridView

DBAccess dba = new DBAccess();
DataTable dt = dba.spGetASTMTable(); // Getting Data from DataBase for Grid
DataTable dtOrders = dba.spGetOrdersList(); / Getting Data from DataBase for ComboBox
// Create ComboBox
var cboDbTableColumn = new DataGridViewComboBoxColumn();
cboDbTableColumn.DataSource = dtOrders;
cboDbTableColumn.DataPropertyName = "OrdersID";
cboDbTableColumn.DisplayMember = "Orders";
cboDbTableColumn.HeaderText = "DbTableColumn";

gvASTMOrderMessage.Columns.Add(cboDbTableColumn);

gvASTMOrderMessage.DataSource = dt;

Then I run my app and change couple ComboBoxes. I Click button "Save" and I want to get DataTable with all DataGridView Data. As I understand, because of my ComboBox is on a part of DataSource then I need to loop through whole Grid and manually add values of ComboBox to my DataTable. I'm trying to do this step here:

private void btnSave_Click(object sender, EventArgs e)
{
     DataTable data = (DataTable)(gvASTMOrderMessage.DataSource);
     data.Columns.Add("DbTableColumn");
     for (int i = 0; i < gvASTMOrderMessage.Rows.Count; i++)
     {
         data.Rows[i]["DbTableColumn"] = Convert.ToString((gvASTMOrderMessage.Rows[i].Cells[0] as DataGridViewComboBoxCell).FormattedValue.ToString());
     }
} 

But this doesn't work. I've tried to get

gvASTMOrderMessage.Rows[i].Cells[0].FormattedValue.ToString()
gvASTMOrderMessage.Rows[i].Cells[0].Value.ToString()
gvASTMOrderMessage.Rows[i].Cells[0].EditedFormattedValue.ToString()

But nothing of this works...

Help please, how to get all values of every combobox from my DataGridView and Add them to DataTable?

Answer 1

DataSource and DataGridView are two different objects which are somehow coordinated. But this coordination is not perfect and, actually, can easily drive to problems (deleting elements from the DataSource and accessing those indices from the DataGridView ). That's why, I always prefer to affect both objects at the same time ( DataSource and DataGridView ).

In any case, bear in mind that quite a few changes you perform in the DataGridView (eg, adding/removing columns) are not automatically reflected in the DataSource (although it can happen inversely). In your specific situation, this behaviour makes still more sense as far as automating the inclusion of a DataGridViewComboBoxColumn type column into a DataSource (perhaps a DataTable , perhaps other object) would be virtually impossible (many alternatives, no one objectively better than the others).

You should come up with a way to fit the comboboxes into your DataTable (for example: populate in the given column as many rows as items in the combobox and "mark" this column in some way) and implement a code performing the corresponding updating actions when required.

Answer 2

Well, you should check the

DataTable data = (DataTable)(gvASTMOrderMessage.DataSource);

check if the datatable is null (mine was). The rest of the code seems ok, also check

data.Rows[i]["DbTableColumn"] = Convert.ToString((gvASTMOrderMessage.Rows[i].Cells[0] as DataGridViewComboBoxCell).FormattedValue.ToString()); }

i would do something like

DataGridViewComboBoxCell cell = (DataGridViewComboBoxCell)dataGridView1.Rows[i].Cells[0];
                data.Rows[i]["DbTableColumn"] = cell.FormattedValue.ToString());

which is a more readable version.

Hope this helps!

Answer 3

Maybe I don't understand something but look the following code: I have added the extra "ComboID" column, and after you have selected items in the gridview and clicked the "Save" button the datatable will contain the IDs from the combo.

    private void Form1_Load(object sender, EventArgs e)
    {
        var dt = new DataTable();
        dt.Columns.Add("Id");
        dt.Columns.Add("Value");
        dt.Columns.Add("ComboID");

        var drow = dt.NewRow();
        drow[0] = 10;
        drow[1] = "abc";
        dt.Rows.Add(drow);

        drow = dt.NewRow();
        drow[0] = 20;
        drow[1] = "xy";
        dt.Rows.Add(drow);

        dataGridView1.AutoGenerateColumns = false;
        dataGridView1.Columns.Add(new DataGridViewTextBoxColumn { DataPropertyName = "Id" });
        dataGridView1.Columns.Add(new DataGridViewTextBoxColumn { DataPropertyName = "Value" });

        var dtOrders = new DataTable();
        dtOrders.Columns.Add("OrdersID");
        dtOrders.Columns.Add("Orders");

        drow = dtOrders.NewRow();
        drow[0] = 1;
        drow[1] = "Order1";
        dtOrders.Rows.Add(drow);

        drow = dtOrders.NewRow();
        drow[0] = 2;
        drow[1] = "Order2";
        dtOrders.Rows.Add(drow);

        var combo = new DataGridViewComboBoxColumn();
        combo.DataSource = dtOrders;
        combo.DataPropertyName = "ComboID";
        combo.ValueMember = "OrdersID";
        combo.DisplayMember = "Orders";
        dataGridView1.Columns.Add(combo);

        dataGridView1.DataSource = dt;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        var dt = dataGridView1.DataSource as DataTable;
    }