DevExpress Combobox in treelist is disabled

Question

I try to show a combobox in my TreeList usiong this code:

RepositoryItemLookUpEdit rep = new RepositoryItemLookUpEdit();
rep.TextEditStyle = TextEditStyles.DisableTextEditor;

//rep = new RepositoryItemComboBox();
//rep.Items.AddRange(new SecuredObject<QuestionnaireCategory>().PermissionType);
//rep.Items.AddRange(new object[] { "A", "B", "C" });


treeList1.RepositoryItems.Add(rep);

TreeListColumn disciplineColumn = treeList1.Columns.Add();
disciplineColumn.Caption = "Discipline";
disciplineColumn.Visible = true;
disciplineColumn.FieldName = "Entity.Description";
disciplineColumn.OptionsColumn.AllowEdit = false;

TreeListColumn permissionColumn = treeList1.Columns.Add();
permissionColumn.Caption = "Permissie";
permissionColumn.Visible = true;
permissionColumn.Name = "Permission";
//permissionColumn.FieldName = "PermissionType";
permissionColumn.UnboundType = UnboundColumnType.Object;
permissionColumn.ColumnEdit = rep;
//permissionColumn.OptionsColumn.ReadOnly = false;
//permissionColumn.OptionsColumn.AllowEdit = true;

rep.DataSource = permissions;
rep.DisplayMember = "Description";
rep.ValueMember = "Id";
rep.Name = "ola";
rep.ThrowExceptionOnInvalidLookUpEditValueType = true;

However, the combo remains empty, it displays '[no data]'. When I set a breakpoint at my datasource, I see that the datasource is filled.

What am I doing wrong?

Answer 1

Most of your code looks ok, so I suspect it maybe either the missing fieldname or some problem with the datasource.

The following is a tiny sample, most of which is a straight copy of your code (slightly indented) , but I am creating the treelist at runtime and have created a sample generic list to use as a datasource to test it.

At the end of the constructor, for unbound mode , I add a few nodes to the tree otherwise I bind to the datasource and set the fieldname on permissionColumn.

using System;
using System.Windows.Forms;
using DevExpress.XtraEditors.Repository;
using DevExpress.XtraTreeList.Columns;
using DevExpress.XtraEditors.Controls;
using DevExpress.XtraTreeList.Data;

public class Form1 : Form
{
    [STAThread]
    static void Main()
    {
        Application.Run(new Form1());
    }

     public Form1()
    {
        this.ClientSize = new System.Drawing.Size(700, 500);
        DevExpress.XtraTreeList.TreeList treeList1 = new DevExpress.XtraTreeList.TreeList();
        this.Controls.Add(treeList1);
        treeList1.Dock = DockStyle.Fill;
        var permissions = new System.Collections.Generic.List<TestClass>();
        permissions.Add(new TestClass() { Id = 1 , Description = "Permission 1" });
        permissions.Add(new TestClass() { Id = 99, Description = "Permission 99" });

        var list = new System.Collections.Generic.List<TestClass2>();
        list.Add(new TestClass2() { Id = 1 , PermissionId = 1 , Description2 = "List Desc 1" });
        list.Add(new TestClass2() { Id = 2 , PermissionId = 99, Description2 = "List Desc 2" });



                // Your code

                RepositoryItemLookUpEdit rep = new RepositoryItemLookUpEdit();
                rep.TextEditStyle = TextEditStyles.DisableTextEditor;

                //rep = new RepositoryItemComboBox();
                //rep.Items.AddRange(new SecuredObject<QuestionnaireCategory>().PermissionType);
                //rep.Items.AddRange(new object[] { "A", "B", "C" });


                treeList1.RepositoryItems.Add(rep);

                TreeListColumn disciplineColumn = treeList1.Columns.Add();
                disciplineColumn.Caption = "Discipline";
                disciplineColumn.Visible = true;
                disciplineColumn.FieldName = "Entity.Description";
                disciplineColumn.OptionsColumn.AllowEdit = false;

                TreeListColumn permissionColumn = treeList1.Columns.Add();
                permissionColumn.Caption = "Permissie";
                permissionColumn.Visible = true;
                permissionColumn.Name = "Permission";
                //permissionColumn.FieldName = "PermissionType";
                permissionColumn.UnboundType = UnboundColumnType.Object;
                permissionColumn.ColumnEdit = rep;
                //permissionColumn.OptionsColumn.ReadOnly = false;
                //permissionColumn.OptionsColumn.AllowEdit = true;

                rep.DataSource = permissions;
                rep.DisplayMember = "Description";
                rep.ValueMember = "Id";
                rep.Name = "ola";
                rep.ThrowExceptionOnInvalidLookUpEditValueType = true;

                // End Your code


        disciplineColumn.FieldName = "Description2";
        bool unBoundMode = false;
        if (unBoundMode)
        {
            treeList1.AppendNode(new object[] { "Item1", 1 }, -1);
            treeList1.AppendNode(new object[] { "Item2", 99 }, -1);
        }
        else
        {
            treeList1.DataSource = list;
            permissionColumn.FieldName = "PermissionId";
        }


    }

}

public class TestClass
{
    public int Id             { get; set; }
    public string Description { get; set; }
}


public class TestClass2
{
    public int Id { get; set; }
    public int PermissionId { get; set; }
    public string Description2 { get; set; }
}

Answer 2

It's that because your setting the column as Unbound

...
permissionColumn.UnboundType = UnboundColumnType.Object;
...

Answer 3

I just went back and checked out Lookup Editors -- I'm pretty sure you need to create columns manually before any data will appear. The DevExpress LookupEditor isn't a simple drop-down, it's basically an embedded grid control. If there's only one property on your item list to display, it would be something like this:

  rep.Columns.Add(new LookupColumnInfo("PropertyName", 0));