錯誤試圖通過ashx的處理程序來顯示圖像時 - 的圖片：「http：//本地主機：57157/......」無法顯示，因爲它包含錯誤

Question

這裏是我的代碼：

HTML：<img src="thumbCreate.ashx?Id=223" alt="asd" />

HTTP處理：`

public void ProcessRequest (HttpContext context) 
    { 
     CreateThumbNail(context); 
    } 
private void CreateThumbNail(HttpContext context) 
{ 
     string resourceId = context.Request.QueryString["Id"]; 
     context.Response.Write("No resource found for Id = " + resourceId); 
     Bitmap original = new Bitmap("C:/Devp/My work/ASHXSampleApp/Images/Desert.jpg"); 
     int oWidth = original.Width; 
     int oHeight = original.Height; 

     int preferredWidth = 80; 
     int preferredHeight = 100; 

     int thumbWidthFactor = oWidth/preferredWidth; 
     int thumbHeightFactor = oHeight/preferredHeight; 

     int maxFactor = Math.Max(thumbWidthFactor, thumbHeightFactor); 

     int thumbNailWidth = oWidth/maxFactor; 
     int thumbNailHeight = oHeight/maxFactor; 
     Bitmap thumbNailImage = (Bitmap)original.GetThumbnailImage(thumbNailWidth, thumbNailHeight, ThumbNailCallback, IntPtr.Zero); 


     context.Response.ContentType = "image/Jpeg"; 
     thumbNailImage.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg); 


}` 

但這代碼不顯示圖像。當我手動嘗試在Firefox中運行處理程序時，它給了我一個錯誤： - 「圖像」http：// localhost：57157/ASHXSampleApp/thumbCreate.ashx？Id = 223「無法顯示，因爲它包含錯誤。任何想法？

Answer 1

問題來自您的代碼的這一部分。

string resourceId = context.Request.QueryString["Id"]; 
context.Response.Write("No resource found for Id = " + resourceId); 

您總是在響應流中添加一個字符串，然後再寫入圖像數據，這會導致字符串損壞。刪除它（或使其有條件，以便在發生錯誤時添加），它應該可以工作。

Answer 2

context.Response.WriteFile（）是否工作？