如何检测是否存在DataGridViewComboBoxColumn

Question

I have a DataGridView with the last column being added on as DataGridViewComboBoxColumn

The problem is, i can determine if the column "Notes" exists by doing

if(grid.Columns.Contains("Notes")){
}

But if i try this same method with the heading of the DataGridViewComboBoxColumn it doesn't work. Can anyone suggest, why it is so?

Here is the function that creates the grid and adds the DataGridViewComboBoxColumn, with Mikhail Tregubov suggested code at the bottom to determine if the column exists already...it doesn't pick it up as being there, even though this function is run previously and it is there!

private void _buildDataTable()
        {

            // create a data table object
            DataTable dataTable = new DataTable();

            // add columns
            dataTable.Columns.Add("Channel");
            dataTable.Columns.Add("Date");
            dataTable.Columns.Add("First Name");
            dataTable.Columns.Add("Last Name");
            dataTable.Columns.Add("DOB");
            dataTable.Columns.Add("NI Number");
            dataTable.Columns.Add("Notes");
            dataTable.Columns.Add("Agg. Max[%]");
            dataTable.Columns.Add("Agg. Inclination[%/min]");
            dataTable.Columns.Add("Agg. LagPhase[s]");

            // CONCENTRATION COL
            // TEST TYPE DROP DOWN COL

            // add initial rows row to data grid for 4 channels - only 4 possible
            DataRow dataRow1 = dataTable.Rows.Add();
            DataRow dataRow2 = dataTable.Rows.Add();
            DataRow dataRow3 = dataTable.Rows.Add();
            DataRow dataRow4 = dataTable.Rows.Add();

            // Add initial data to the new rows
            dataRow1[0] = "1"; // channel number
            dataRow1[1] = DateTime.Now.ToString("d/M/yyyy");
            dataRow1[7] = "0";
            dataRow1[8] = "0";
            dataRow1[9] = "0";
            dataRow2[0] = "2"; // channel number
            dataRow2[1] = DateTime.Now.ToString("d/M/yyyy");
            dataRow2[7] = "0";
            dataRow2[8] = "0";
            dataRow2[9] = "0";
            dataRow3[0] = "3"; // channel number
            dataRow3[1] = DateTime.Now.ToString("d/M/yyyy");
            dataRow3[7] = "0";
            dataRow3[8] = "0";
            dataRow3[9] = "0";
            dataRow4[0] = "4"; // channel number
            dataRow4[1] = DateTime.Now.ToString("d/M/yyyy");
            dataRow4[7] = "0";
            dataRow4[8] = "0";
            dataRow4[9] = "0";

            // Add drop downs to the table for test type
            DataGridViewComboBoxColumn testTypeCol = new DataGridViewComboBoxColumn();

            // create a new datatable for the test type
            DataTable dataTable2 = new DataTable();

            // Add the column
            dataTable2.Columns.Add(new DataColumn("Value", typeof(string)));

            // Add drop down rows
            dataTable2.Rows.Add("A23187");
            dataTable2.Rows.Add("ADP");
            dataTable2.Rows.Add("Arachidonic Acid");
            dataTable2.Rows.Add("Collagen");
            dataTable2.Rows.Add("CRP");
            dataTable2.Rows.Add("Epinephrine");
            dataTable2.Rows.Add("PMA");
            dataTable2.Rows.Add("Ristocetin");
            dataTable2.Rows.Add("TRAP6");
            dataTable2.Rows.Add("U46619");
            dataTable2.Rows.Add("γ-Thrombin");

            // set the columns data source
            testTypeCol.DataSource = dataTable2;

            // set properties
            testTypeCol.ValueMember = "Value";
            testTypeCol.HeaderText = "Aggregation Test Type";

            // set the data in the gridview
            this._dataGrid.DataSource = dataTable;

            if (this._dataGrid.Columns.Contains("Aggregation Test Type") && this._dataGrid.Columns["Aggregation Test Type"].GetType() == typeof(DataGridViewComboBoxColumn))
            {
                MessageBox.Show("ALREADY");
            }
            else
            {
                // add column to the datagridview
                this._dataGrid.Columns.Add(testTypeCol);
            }

        }

Answer 1

If your question is how to determine if the column type is DataGridViewComboBoxColumn then try use a typeof. Ex:

        if(grid.Columns.Contains("Notes") && grid.Columns["Notes"].GetType() == typeof(DataGridViewComboBoxColumn))
        {
            //do something
        }

If your problem is that the method Contains doesn't work properly with DataGridViewComboBoxColumn added to grid.Columns collection then please add more code for example of how you creating new instance of DataGridViewComboBoxColumn and add it to your grid.