TextRange.Load(Stream, String) 方法

  • 参考

定义

命名空间:
System.Windows.Documents
程序集:
PresentationFramework.dll

从指定流加载采用指定数据格式的当前所选内容。

public:
 void Load(System::IO::Stream ^ stream, System::String ^ dataFormat);
public void Load (System.IO.Stream stream, string dataFormat);
member this.Load : System.IO.Stream * string -> unit
Public Sub Load (stream As Stream, dataFormat As String)

参数

stream
Stream

包含要加载到当前所选内容中的数据的可读流。

dataFormat
String

要将数据加载为的数据格式。 当前支持的数据格式是 Rtf、Text、Xaml 和 XamlPackage。

例外

ArgumentNullException

当 stream 或 dataFormat 为 null 时发生。

ArgumentException

当不支持指定数据格式时发生。 如果从 stream 加载的内容与指定数据格式不匹配，也可能引发。

示例

下面的示例演示 Load 方法的用法。

// 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

注解

true如果 CanSeek 为 stream，则内容将从流的开头加载到流的末尾。 否则，将从当前 Position 到流末尾读取内容。 此方法返回时， stream 将保持打开状态，并且未定义中的 stream 当前位置。

加载操作将当前所选内容替换为新加载的内容。

适用于

另请参阅