While binding data to RadTreeView I am getting an error 
"These columns don't currently have unique values."

Below is the dataset which I am binding to RadTree

ParentID    ChildID    Label    Visible    Type
NULL             1 Category true Category
NULL 2 Brand true Brand
NULL 3 SubBrand1 true SubBrand1
NULL 4 SubBrand2 true SubBrand2
1 1_52 1_Consumer false Category
1 1_53 1_Business false Category
1 1_54 1_Total false Category
1 1_72 1_Sprint false Category
1 1_73 1_Nextel false Category
1 1_189 1_SprintNextel true Category
1 1_190 1_ATTCingular true Category
1 1_191 1_ATT true Category
1 1_192 1_Cingular true Category
1 1_193 1_TMobile true Category
1 1_194 1_Verizon true Category
2 2_137 2_Sprint false Brand
2 2_138 2_Nextel true Brand
2 2_224 2_Business true Brand
2 2_225 2_Consumer true Brand
2 2_226 2_Total false Brand
3 3_246 3_Wireless true SubBrand 1
4 4_194 4_Total true SubBrand 2

Hi Meghna,

I couldn't reproduce this issue using the following code:

    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);

        DataTable data = new DataTable();
        data.Columns.Add("ParentID");
        data.Columns.Add("ChildID");
        data.Columns.Add("Label");
        data.Columns.Add("Visible");
        data.Columns.Add("Type");

        data.Rows.Add(null, "1", "Category", "true", "Category");
        data.Rows.Add(null, "2", "Brand", "true", "Brand");
        data.Rows.Add(null, "3", "SubBrand1", "true", "SubBrand1");
        data.Rows.Add(null, "4", "SubBrand2", "true", "SubBrand2");
        data.Rows.Add("1", "1_52", "1_Consumer", "false", "Category");
        data.Rows.Add("1", "1_53", "1_Business", "false", "Category");
        data.Rows.Add("1", "1_54", "1_Total", "false", "Category");
        data.Rows.Add("1", "1_72", "1_Sprint", "false", "Category");
        data.Rows.Add("1", "1_73", "1_Nextel", "false", "Category");
        data.Rows.Add("1", "1_189", "1_SprintNextel", "true", "Category");
        data.Rows.Add("1", "1_190", "1_ATTCingular", "true", "Category");
        data.Rows.Add("1", "1_191", "1_ATT", "true", "Category");
        data.Rows.Add("1", "1_192", "1_Cingular", "true", "Category");
        data.Rows.Add("1", "1_193", "1_TMobile", "true", "Category");
        data.Rows.Add("1", "1_194", "1_Verizon", "true", "Category");
        data.Rows.Add("2", "2_137", "2_Sprint", "false", "Brand");
        data.Rows.Add("2", "2_138", "2_Nextel", "true", "Brand");
        data.Rows.Add("2", "2_224", "2_Business", "true", "Brand");
        data.Rows.Add("2", "2_225", "2_Consumer", "true", "Brand");
        data.Rows.Add("2", "2_226", "2_Total", "false", "Brand");
        data.Rows.Add("3", "3_246", "3_Wireless", "true", "SubBrand");
        data.Rows.Add("4", "4_194", "4_Total", "true", "SubBrand");

        RadTreeView1.DataFieldID = "ChildID";
        RadTreeView1.DataFieldParentID = "ParentID";
        RadTreeView1.DataTextField = "Label";
        RadTreeView1.DataSource = data;
        RadTreeView1.DataBind();
    }

What is different in your case?

Regards,
Albert
the Telerik team