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Working with Content Controls
Updated on May 7, 2026
This article shows some examples of how you can access a content control and modify their properties from the code. In general, the content controls are marked with annotations and you can manipulate them as such. Detailed information is available here: Manipulating Annotations
Manipulate existing content controls
Get the content controls.
The content controls can be retrieved by using the GetAnnotationMarkersOfType method. This is demonstrated in the following example.
Example 1: Get all Content Controls
C#
IEnumerable<SdtRangeStart> content_controls = this.radRichTextEditor1.Document.GetAnnotationMarkersOfType<SdtRangeStart>();
foreach (var item in content_controls)
{
Console.WriteLine("Type: {0} ID:{1}", item.SdtProperties.Type, item.SdtProperties.ID);
}Set content controls properties.
This example shows how you can iterate the items and add an item to a existing ComboBox content control.
Example 2: Adding items to a ComboBox or a DropDownList
C#
foreach (var item in content_controls)
{
if (item.SdtProperties.Type == SdtType.ComboBox)
{
ComboBoxProperties properties = item.SdtProperties as ComboBoxProperties;
ListItem newItem = new ListItem();
newItem.DisplayText = "New Item Text";
properties.Items.Add(newItem);
}
}Insert new content controls
New content controls can be inserted trough one of the overloads of the InsertStructuredDocumentTag method accessible from RadRichTextEditor and RadDocumentEditor:
Example 3: Inserting a content control
C#
this.radRichTextEditor1.InsertStructuredDocumentTag();
// OR
RadDocumentEditor editor = new RadDocumentEditor(this.radRichTextEditor1.Document);
editor.InsertStructuredDocumentTag();Example 4: Inserting a content control using content control type
C#
this.radRichTextEditor1.InsertStructuredDocumentTag(SdtType.CheckBox);
// OR
RadDocumentEditor editor = new RadDocumentEditor(this.radRichTextEditor1.Document);
editor.InsertStructuredDocumentTag(SdtType.CheckBox);Example 5: Inserting a content control using content control properties
C#
SdtProperties sdtProperties = new SdtProperties(SdtType.RichText)
{
Alias = "AliasName",
Lock = Lock.SdtContentLocked,
};
this.radRichTextEditor1.InsertStructuredDocumentTag(sdtProperties);
// OR
RadDocumentEditor editor = new RadDocumentEditor(this.radRichTextEditor1.Document);
editor.InsertStructuredDocumentTag(sdtProperties);