Self-reference hierarchy using List<Object>

[David zhao]

Hi.
When I used List<object> type as datasource for self-reference hierarchy, I had a problem.
Here is my grid definition:
<telerik:RadGrid ID="RadGrid2" runat="server" DataSourceID="ObjectDataSource1"
            oncolumncreated="RadGrid2_ColumnCreated"
            onitemcreated="RadGrid2_ItemCreated"
            onitemdatabound="RadGrid2_ItemDataBound" CellSpacing="0" GridLines="None">
            <MasterTableView HierarchyLoadMode="Client" HierarchyDefaultExpanded="true"
                Width="100%"  AutoGenerateColumns="False" DataSourceID="ObjectDataSource1" DataKeyNames="ID, ParentID">
                <SelfHierarchySettings ParentKeyName="ParentID" KeyName="ID" />
                <Columns>
                    <telerik:GridBoundColumn DataField="ID" DataType="System.Int32"
                        FilterControlAltText="Filter ID column" HeaderText="ID" SortExpression="ID"
                        UniqueName="ID">
                    </telerik:GridBoundColumn>
                    <telerik:GridBoundColumn DataField="ParentID" DataType="System.Int32"
                        FilterControlAltText="Filter ParentID column" HeaderText="ParentID"
                        SortExpression="ParentID" UniqueName="ParentID">
                    </telerik:GridBoundColumn>
                    <telerik:GridBoundColumn DataField="Name"
                        FilterControlAltText="Filter Name column"
                        HeaderText="Name" SortExpression="Name"
                        UniqueName="Name">
                    </telerik:GridBoundColumn>
                </Columns>
            </MasterTableView>
            <ClientSettings AllowExpandCollapse="true" />
        </telerik:RadGrid>

    <telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
        <AjaxSettings>
            <telerik:AjaxSetting AjaxControlID="RadGrid2">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadGrid2" />
                </UpdatedControls>
            </telerik:AjaxSetting>
        </AjaxSettings>
    </telerik:RadAjaxManager>
    <asp:ObjectDataSource ID="ObjectDataSource1" runat="server"
        SelectMethod="GetAllTest"
        TypeName="BLL.Test">       
    </asp:ObjectDataSource>
    <telerik:RadScriptManager ID="RadScriptManager1" Runat="server">
    </telerik:RadScriptManager>

===============
Here is my code

    protected void Page_Load(object sender, EventArgs e)
    {      
        RadGrid2.MasterTableView.FilterExpression = @"it[""ParentID""] == 0";      
    }

    public void Page_PreRenderComplete(object sender, EventArgs e)
    {
        HideExpandColumnRecursive(RadGrid2.MasterTableView);
    }

    protected void RadGrid2_ItemCreated(object sender, Telerik.Web.UI.GridItemEventArgs e)
    {
        CreateExpandCollapseButton(e.Item, "ID");
        if (e.Item is GridHeaderItem && e.Item.OwnerTableView != RadGrid2.MasterTableView)
        {
            e.Item.Style["display"] = "none";
        }
        if (e.Item is GridNestedViewItem)
        {
            e.Item.Cells[0].Visible = false;
        }
    }

    protected void RadGrid2_ColumnCreated(object sender, Telerik.Web.UI.GridColumnCreatedEventArgs e)
    {
        if (e.Column is GridExpandColumn)
        {
            e.Column.Visible = false;
        }
        else if (e.Column is GridBoundColumn)
        {
            e.Column.HeaderStyle.Width = Unit.Pixel(100);
        }
    }

    public void HideExpandColumnRecursive(GridTableView tableView)
    {
        GridItem[] nestedViewItems = tableView.GetItems(GridItemType.NestedView);
        foreach (GridNestedViewItem nestedViewItem in nestedViewItems)
        {
            foreach (GridTableView nestedView in nestedViewItem.NestedTableViews)
            {
                nestedView.Style["border"] = "0";

                Button MyExpandCollapseButton = (Button)nestedView.ParentItem.FindControl("MyExpandCollapseButton");
                if (nestedView.Items.Count == 0)
                {
                    if (MyExpandCollapseButton != null)
                    {
                        MyExpandCollapseButton.Style["visibility"] = "hidden";
                    }
                    nestedViewItem.Visible = false;
                }
                else
                {
                    if (MyExpandCollapseButton != null)
                    {
                        MyExpandCollapseButton.Style.Remove("visibility");
                    }
                }

                if (nestedView.HasDetailTables)
                {
                    HideExpandColumnRecursive(nestedView);
                }
            }
        }
    }

    protected void RadGrid2_ItemDataBound(object sender, GridItemEventArgs e)
    {
        CreateExpandCollapseButton(e.Item, "ID");
    }

    public void CreateExpandCollapseButton(GridItem item, string columnUniqueName)
    {
        if (item is GridDataItem)
        {
            if (item.FindControl("MyExpandCollapseButton") == null)
            {
                Button button = new Button();
                button.Click += new EventHandler(button_Click);
                button.CommandName = "ExpandCollapse";
                button.CssClass = (item.Expanded) ? "rgCollapse" : "rgExpand";
                button.ID = "MyExpandCollapseButton";

                if (item.OwnerTableView.HierarchyLoadMode == GridChildLoadMode.Client)
                {
                    string script = String.Format(@"$find(""{0}"")._toggleExpand(this, event); return false;", item.Parent.Parent.ClientID);

                    button.OnClientClick = script;
                }

                int level = item.ItemIndexHierarchical.Split(':').Length - 1;

                button.Style["margin-left"] = level * 15 + "px";

                TableCell cell = ((GridDataItem)item)[columnUniqueName];
                cell.Controls.Add(button);
                cell.Controls.Add(new LiteralControl("&nbsp;"));
                cell.Controls.Add(new LiteralControl(((GridDataItem)item).GetDataKeyValue(columnUniqueName).ToString()));
            }
        }        
    }

    void button_Click(object sender, EventArgs e)
    {
        ((Button)sender).CssClass = (((Button)sender).CssClass == "rgExpand") ? "rgCollapse" : "rgExpand";
    }
==================
here is my BLL code

public class Test
    {
        private static readonly ITestDAL dal = DataAccess.CreateTestDAL();

        public static List<TestEntity> GetAllTest()
        {
            List<TestEntity> result = null;

            try
            {
                result = dal.GetAllTest();
            }
            catch (Exception ex)
            {
               .....
            }           

            return result;
        }
    }
==================
public class TestEntity
    {      
        private int id;
        private int parentID;
        private string name;

        public int ID
        {
            get { return this.id; }
            set { this.id = value; }
        }

        public int ParentID
        {
            get { return this.parentID; }
            set { this.parentID = value; }
        }

        public string Name
        {
            get { return this.name; }
            set { this.name = value; }
        }

        public TestEntity()
        {
        }

        public TestEntity(int id, int parentID, string name)
        {
            this.id = id;
            this.parentID = parentID;
            this.name = name;
        }

    }

==================
here is error message:
ExceptionType:Telerik.Web.UI.ParseException
ErrorMessage:No applicable indexer exists in type 'TestEntity'
ErrorSource:Telerik.Web.UI

==================
Can you please find the reason for the error ? Or , can you tell me how to realize self-reference hierarchy with List<Object> as datasource

[Iana Tsolova]

Hi David,

In order to implement self-referencing grid with you custom objects and collection, you should disable grid linq expressions. Check the attached demo.

Kind regards,
Iana Tsolova
the Telerik team

[David zhao]

Iana Tsolova:

      Thank you very much!

      The demo you given works well.  I tried it and  found my error. In my codes, FilterExpression is wrong.