TextRange.IsEmpty Property
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Gets a value indicating whether or not the current selection is empty.
public:
property bool IsEmpty { bool get(); };
C#
public bool IsEmpty { get; }
member this.IsEmpty : bool
Public ReadOnly Property IsEmpty As Boolean
true
if the current selection is empty; otherwise, false
.
The following example demonstrates the use of the IsEmpty property.
C#
// This method accepts an input stream and a corresponding data format. The method
// will attempt to load the input stream into a TextRange selection, apply Bold formatting
// to the selection, save the reformatted selection to an alternat stream, and return
// the reformatted stream.
Stream BoldFormatStream(Stream inputStream, string dataFormat)
{
// A text container to read the stream into.
FlowDocument workDoc = new FlowDocument();
TextRange selection = new TextRange(workDoc.ContentStart, workDoc.ContentEnd);
Stream outputStream = new MemoryStream();
try
{
// Check for a valid data format, and then attempt to load the input stream
// into the current selection. Note that CanLoad ONLY checks whether dataFormat
// is a currently supported data format for loading a TextRange. It does not
// verify that the stream actually contains the specified format. An exception
// may be raised when there is a mismatch between the specified data format and
// the data in the stream.
if (selection.CanLoad(dataFormat))
selection.Load(inputStream, dataFormat);
}
catch (Exception e) { return outputStream; /* Load failure; return a null stream. */ }
// Apply Bold formatting to the selection, if it is not empty.
if (!selection.IsEmpty)
selection.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold);
// Save the formatted selection to a stream, and return the stream.
if (selection.CanSave(dataFormat))
selection.Save(outputStream, dataFormat);
return outputStream;
}
' This method accepts an input stream and a corresponding data format. The method
' will attempt to load the input stream into a TextRange selection, apply Bold formatting
' to the selection, save the reformatted selection to an alternat stream, and return
' the reformatted stream.
Private Function BoldFormatStream(ByVal inputStream As Stream, ByVal dataFormat As String) As Stream
' A text container to read the stream into.
Dim workDoc As New FlowDocument()
Dim selection As New TextRange(workDoc.ContentStart, workDoc.ContentEnd)
Dim outputStream As Stream = New MemoryStream()
Try
' Check for a valid data format, and then attempt to load the input stream
' into the current selection. Note that CanLoad ONLY checks whether dataFormat
' is a currently supported data format for loading a TextRange. It does not
' verify that the stream actually contains the specified format. An exception
' may be raised when there is a mismatch between the specified data format and
' the data in the stream.
If selection.CanLoad(dataFormat) Then
selection.Load(inputStream, dataFormat)
End If
Catch e As Exception ' Load failure return a null stream.
Return outputStream
End Try
' Apply Bold formatting to the selection, if it is not empty.
If Not selection.IsEmpty Then
selection.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold)
End If
' Save the formatted selection to a stream, and return the stream.
If selection.CanSave(dataFormat) Then
selection.Save(outputStream, dataFormat)
End If
Return outputStream
End Function
A TextRange is considered empty if the Start and End positions are equal.
제품 | 버전 |
---|---|
.NET Framework | 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
Windows Desktop | 3.0, 3.1, 5, 6, 7, 8, 9 |
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