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How to Pre-Select a Node Based on Text or Value

How to pre-select a node by text or value

There are two options to pre-select a value in the RadDropDownTree when it is bound to a datasource - you can pre-select a node by its text or its value property. For the text the SelectedText can be used while for the value, one needs to use the SelectedValue one.For instance in a simple scenario this can be achieved by using the following data-bind expression:

note

These properties are available after the Q2 2013 release of the Telerik controls.

<telerik:raddropdowntree runat="server" id="RadDropDownTreeTest" datatextfield="LastName"
    datafieldparentid="ReportsTo" datafieldid="EmployeeID" ondatabound="RadDropDownTreeTest_DataBound"
    datavaluefield="EmployeeID" datasourceid="SqlDataSource2" selectedvalue='<%#Bind("EmployeeID") %>'>
    <DropDownSettings OpenDropDownOnLoad="true" />
</telerik:raddropdowntree>

How to pre-select more than one node when checkboxes are enabled

This section describes how one can pre-select several nodes in the scenario when checkboxes are enabled (in other words, when more that one node can be selected). In such case the SelectedValue and SelectedText properties can be set from code behind. It is, however, important to notice that in this case there is a delimiter separating the nodes. By default, the text of the entries in the entry area is separated by a semicolon and therefore a semicolon needs to be used when selecting more than one node. However, this can easily be changed by using the EntriesDelimiter property. Note, that you will also need to change the delimiter that is used in the code behind when the SelectedText is set.

In contrast to that, when the SelectedValue property is set in the code behind, the values for the nodes are separated by comma. Below you can find and example how to select few nodes from the RadDropDownTree when using SelectedValue and/or SelectedText property.

<telerik:RadDropDownTree RenderMode="Lightweight" runat="server" Skin="Default" ID="RadDropDownTreeTest" DataTextField="LastName" DataFieldParentID="ReportsTo"
    DataFieldID="EmployeeID" OnDataBound="RadDropDownTreeTest_DataBound" CheckBoxes="TriState"
    DataValueField="EmployeeID" DataSourceID="SqlDataSource2">
    <DropDownSettings OpenDropDownOnLoad="true" />

</telerik:RadDropDownTree>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
    SelectCommand="SELECT EmployeeID, ReportsTo, LastName FROM [Employees]"></asp:SqlDataSource>
protected void RadDropDownTreeTest_DataBound(object sender, System.EventArgs e)
{
    ((RadDropDownTree)sender).ExpandAllDropDownNodes();
    //either of the two methods can be used to select a node by using text
    RadDropDownTreeTest.SelectedText = "Davolio" + ";" + "Leverling";
    //RadDropDownTreeTest.SelectedText = "Davolio; Leverling";
    //the value of the nodes are separated by a comma 
    RadDropDownTreeTest.SelectedValue = "3,4";
}   
Protected Sub RadDropDownTreeTest_DataBound(sender As Object, e As System.EventArgs)
    DirectCast(sender, RadDropDownTree).ExpandAllDropDownNodes()
    'either of the two methods can be used to select a node by using text
    RadDropDownTreeTest.SelectedText = "Davolio" + ";" + "Leverling"
    'RadDropDownTreeTest.SelectedText = "Davolio; Leverling";
    'the value of the nodes are separated by a comma 
    RadDropDownTreeTest.SelectedValue = "3,4"

End Sub