SubDocument Document { get; }

ReadOnly Property Document As SubDocument

Document document = server.Document;
document.LoadDocument("Documents\\Grimm.docx", DocumentFormat.Docx);
// Access a text box in the document.
Shape myTextBox = document.Shapes[0];
// Specify that the text box should resize to fit its content.
myTextBox.ShapeFormat.TextBox.ResizeShapeToFitText = true;
// Access text box content.
SubDocument boxedDocument = myTextBox.ShapeFormat.TextBox.Document;
int appendPosition = myTextBox.ShapeFormat.TextBox.Document.Range.End.ToInt();
// Append the second paragraph of the main document to the text box.
DocumentRange newRange = boxedDocument.AppendDocumentContent(document.Paragraphs[1].Range);
boxedDocument.Paragraphs.Insert(newRange.Start);
// Insert an image form the main document into the text box.
boxedDocument.Images.Insert(boxedDocument.CreatePosition(appendPosition), document.Images[0].Image.NativeImage);
// Resize the image so that its size equals the image in the main document.
boxedDocument.Images[0].Size = document.Images[0].Size;

Dim document As Document = server.Document
document.LoadDocument("Documents\Grimm.docx", DocumentFormat.Docx)
' Access a text box in the document.
Dim myTextBox As Shape = document.Shapes(0)
' Specify that the text box should resize to fit its content.
myTextBox.ShapeFormat.TextBox.ResizeShapeToFitText = True
' Access text box content.
Dim boxedDocument As SubDocument = myTextBox.ShapeFormat.TextBox.Document
Dim appendPosition As Integer = myTextBox.ShapeFormat.TextBox.Document.Range.End.ToInt()
' Append the second paragraph of the main document to the text box.
Dim newRange As DocumentRange = boxedDocument.AppendDocumentContent(document.Paragraphs(1).Range)
boxedDocument.Paragraphs.Insert(newRange.Start)
' Insert an image form the main document into the text box.
boxedDocument.Images.Insert(boxedDocument.CreatePosition(appendPosition), document.Images(0).Image.NativeImage)
' Resize the image so that its size equals the image in the main document.
boxedDocument.Images(0).Size = document.Images(0).Size

// Modify text box content.
SubDocument textBoxDocument = myTextBox.ShapeFormat.TextBox.Document;
textBoxDocument.AppendText("TextBox Text");

// Modify text box content.
SubDocument textBoxDocument = myTextBox.ShapeFormat.TextBox.Document;
textBoxDocument.AppendText("TextBox Text");

// Modify text box content.
SubDocument textBoxDocument = myTextBox.ShapeFormat.TextBox.Document;
textBoxDocument.AppendText("TextBox Text");

if (shape.ShapeFormat.TextBox != null)
            subDocumentProcessor(shape.ShapeFormat.TextBox.Document);
}

if (shape.ShapeFormat.TextBox != null)
            subDocumentProcessor(shape.ShapeFormat.TextBox.Document);
}

' Modify text box content.
Dim textBoxDocument As DevExpress.XtraRichEdit.API.Native.SubDocument = myTextBox.ShapeFormat.TextBox.Document
textBoxDocument.AppendText("TextBox Text")

' Modify text box content.
Dim textBoxDocument As SubDocument = myTextBox.ShapeFormat.TextBox.Document
textBoxDocument.AppendText("TextBox Text")

' Modify text box content.
Dim textBoxDocument As DevExpress.XtraRichEdit.API.Native.SubDocument = myTextBox.ShapeFormat.TextBox.Document
textBoxDocument.AppendText("TextBox Text")

For Each shape As Shape In shapes
    If shape.ShapeFormat.TextBox IsNot Nothing Then subDocumentProcessor(shape.ShapeFormat.TextBox.Document)
Next

For Each shape As Shape In shapes
    If shape.ShapeFormat.TextBox IsNot Nothing Then subDocumentProcessor(shape.ShapeFormat.TextBox.Document)
Next