This is my data on datasource-

<

 

telerik:RadTreeView ID="RadTreeView1" runat="server" DataSourceID="ObjectDataSourceCompany"

 

 

DataTextField="COMPANYNAME" DataFieldID="CATEGORYID" DataFieldParentID="COMPANYID"

 

 

DataValueField="CATEGORYID">

 

 

</telerik:RadTreeView>

This is the Error-

 

This constraint cannot be enabled as not all values have corresponding parent values.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: This constraint cannot be enabled as not all values have corresponding parent values.

Did I miss anything...How do i fix this??

Hello Jo,

The ParentID of the root items should be null. If for some reason the data source comes without null values for the ParentID column, the solution is to create a query that returns the expected value (null). Check out the code below which shows how to convert ParentID= 0 to ParentID=null
SELECT ID, Text, IF(ParentID = 0, NULL, ParentID) FROM table

You may also go throught he following links which refers to the above mentioned:
Treeview Problem

-Princy.

Or you can use:

SELECT
    ID, Text,
    CASE WHEN ParentID=0
        THEN NULL
         ELSE ParentID
    FROM table