RichTextBox - InvalidOperationException：調用線程必須是STA

Question

我試圖使用MSDN的Converting between RTF and HTML庫將一些RTF文本轉換爲HTML。我的設置的jist是從JavaScript到C＃處理程序的AJAX調用，它調用此MarkupConverter庫進行轉換，然後寫回HTML。

這裏是我的JavaScript：

$.ajax({ 
    type: "POST", 
    url: "MyHandler.ashx", 
    data: richTextData, 
    success: function (html) { 
      alert('success, html: ' + html); 
    }, 
    error: function (msg) { 
      alert("error: " + msg); 
    } 
}); 

而且從我的處理程序，這也是很簡單的代碼：

public void ProcessRequest(HttpContext context) 
{ 
    if (context.Request.Form.Count > 0) 
    { 
     string rtf = context.Request.Form[0]; 
     string html = ""; 
     if (rtf != "") 
     { 
     markupConverter = new MarkupConverter.MarkupConverter(); 
     html = markupConverter.ConvertRtfToHtml(rtf); 
     } 
     if (html != "") 
     { 
     context.Response.ContentType = "text/html"; 
     context.Response.Write(html); 
     } 
     else 
     { 
     context.Response.ContentType = "text/plain"; 
     context.Response.Write("Error from RTF2HTML"); 
     } 
    } 
} 

的問題是，每到這個運行時，一個異常被拋出，因爲RichTextBox控制在後臺線程上創建：

[InvalidOperationException：調用threa d必須STA，因爲許多 UI組件需要此。]
System.Windows.Input.InputManager..ctor（）11032206
System.Windows.Input.InputManager.GetCurrentInputManagerImpl（）125個
System.Windows .Input.KeyboardNavigation..ctor（）185個
System.Windows.FrameworkElement.EnsureFrameworkServices（）109
System.Windows.FrameworkElement..ctor（）504
System.Windows.Controls.Control..ctor （）+87
System.Windows.Controls.RichTextBox..ctor（FlowDocument document）+56
MarkupConverter.RtfToHtmlConv erter.ConvertRtfToXaml（字符串rtfText） +67 MarkupConverter.RtfToHtmlConverter.ConvertRtfToHtml（字符串rtfText）+23 MyHandler.ProcessRequest（HttpContext的背景下）416

我想也許是因爲AJAX調用臺異步，呼叫被越來越放置在後臺線程上。所以我改成了這樣：

var postText = $.ajax({ 
    type: "POST", 
    url: "RTF2HTML.ashx", 
    data: textData, 
    async: false 
}).responseText; 
alert(postText); 

但是即便這樣，當我檢查我的處理程序當前線程：

context.Response.Write("thread: " + System.Threading.Thread.CurrentThread.GetApartmentState().ToString()); 

它仍然返回MTA。

有沒有辦法掛鉤到主STA線程，或者我將不得不創建一個新線程並指定STA？如果是這樣的話，我如何設置回調函數來返回我目前使用的HTML Response.Write？

Answer 1

這可能是有用的：

How to run something in the STA thread?

也許你可以撥打電話，以...

html = markupConverter.ConvertRtfToHtml(rtf); 

...上以同樣的方式在不同的線程？

string rtf; 

public void ProcessRequest(HttpContext context) 
{ 
    if (context.Request.Form.Count > 0) 
    { 
     rtf = context.Request.Form[0]; 
     string html = ""; 
     if (rtf != "") 
     { 
     Thread thread = new Thread(ConvertMarkup); 
      thread.SetApartmentState(ApartmentState.STA); 
      thread.Start(); 
      thread.Join(); 
     } 
     if (html != "") 
     { 
     context.Response.ContentType = "text/html"; 
     context.Response.Write(html); 
     } 
     else 
     { 
     context.Response.ContentType = "text/plain"; 
     context.Response.Write("Error from RTF2HTML"); 
     } 
    } 
} 

void ConvertMarkup() 
{ 
    markupConverter = new MarkupConverter.MarkupConverter(); 
    html = markupConverter.ConvertRtfToHtml(rtf); 
} 

Answer 2

using System.Threading; 

    Thread t = new Thread(new ThreadStart(ProcessRequest)); 

    // Make sure to set the apartment state BEFORE starting the thread. 
    t.ApartmentState = ApartmentState.STA; 
    t.Start(); 

    public void ProcessRequest(HttpContext context) 
    { 
     if (context.Request.Form.Count > 0) 
     { 
     string rtf = context.Request.Form[0]; 
     string html = ""; 
     if (rtf != "") 
     { 
      markupConverter = new MarkupConverter.MarkupConverter(); 
      html = markupConverter.ConvertRtfToHtml(rtf); 
     } 
     if (html != "") 
     { 
      context.Response.ContentType = "text/html"; 
      context.Response.Write(html); 
     } 
     else 
     { 
      context.Response.ContentType = "text/plain"; 
      context.Response.Write("Error from RTF2HTML"); 
     } 
    } 
    }