How to select the newly added new item in GridviewComboBoxColumn (DropDown style)

Hello, Sebastien, 

The provided sample code snippet is greatly appreciated.

Note that the GridViewComboBoxColumn accepts only valid values according to the applied DataSource to the column. If you enter any custom input (that doesn't match any record in the drop down items), it wouldn't be considered as valid. Hence, it won't be stored to the cell.

If you need to allow the end-users to add custom values, it would be necessary this new value to be added to the DataSource collection that is applied to the column. Please refer to the following help article which demonstrates a sample approach: https://docs.telerik.com/devtools/winforms/controls/gridview/editors/how-to/allow-end-users-to-add-items-to-dropdownlisteditor

However, if you type exactly the same text as one of the items that are available in the drop down, it is expected to be preserved in the cell. But it would be necessary to sync the selection in the editor with the entered text either via opening the drop down or by enabling the autocomplete functionality as follows: 

this.radGridView1.CellEditorInitialized+=radGridView1_CellEditorInitialized;

private void radGridView1_CellEditorInitialized(object sender, GridViewCellEventArgs e)
{
    RadDropDownListEditor editor = e.ActiveEditor as RadDropDownListEditor;
    if (editor!=null)
    {
        RadDropDownListEditorElement el = editor.EditorElement as RadDropDownListEditorElement;
        el.AutoCompleteMode = AutoCompleteMode.Append; 
    }
}

Thus, if you enter edit mode (cell value = "Type 1"), don't open the drop down and just type "Type 2", it will be preserved as cell's value. 

I hope this information helps. If you need any further assistance please don't hesitate to contact me.

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik

Thanks Dess,

I managed to modify the test code but I'm still missing something, maybe only a refresh of the row or cell?

double-click on "Type 1", type any text and change the column. The new typed item is not showned, but if you open the editor (double-click on the same cell), the new item is there AND is selected.

Code:

Hello, Sebastien,

I have updated the sample project using the latest code you provided. Indeed, the newly entered value is not displayed in the cell after exiting edit mode. However, the value is successfully added to the _list collection and stored in the cell. This is because you are using a List, not BindingList. BindingList implements the ListChanged event, which is raised when you add, remove, or set items. Bound controls listen to this event in order to know when to refresh their display.

It is just necessary to replace this part of the code: 

private List<KeyValuePair<string, string>> _list;

// some other code

_list = new List<KeyValuePair<string, string>>();

private BindingList<KeyValuePair<string, string>> _list;

// some other code

_list = new BindingList<KeyValuePair<string, string>>();

Additional information is available in the following threads:

https://stackoverflow.com/questions/2243950/listt-vs-bindinglistt-advantages-disadvantages 

https://social.msdn.microsoft.com/Forums/vstudio/en-US/a7312df5-e336-43ea-8393-6ffd17fe1ac6/whats-the-diff-between-listt-and-bindinglistt?forum=csharpgeneral

Should you have further questions please let me know.

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik

It worked on the test project, but I applied the same basics on the client's project and got an exception inside the new control.

There is a NullException thrown in the "EndEdit" method, when I do the "retireCtl.RadGridView.CurrentRow.Cells["columnCombo"].Value = id;"

Any idea? thanks

Here's the stack trace:

Forgot to put the code of my method:

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik

I don't know what I've done, but its working, was my fault for the last error.

thank you Dess, like always : great help from you!