当我取消openfiledialog时如何防止异常？ [英] How can I prevent an exception when I cancel an openfiledialog?

问题描述

我的程序有一个按钮，当点击打开一个openfiledialog来选择图片：

 私人字符串ChoosePicture（）
 {
 fDialog.Title =选择图片; 
 fDialog.Filter =图像文件（* .bmp，* .gif，* .jpg）| * .bmp; * .gif *; *。 
 fDialog.InitialDirectory =C：; 
 fDialog.ShowDialog（）; 
 
 fDialog.AddExtension = true; 
 fDialog.CheckFileExists = true; 
 fDialog.CheckPathExists = true; 
 
 //返回目录的字符串
 return fDialog.FileName.ToString（）; 
} 
  

使用对话框中的检查框还没有解决我的问题： / p>

  fDialog.AddExtension = true; 
 fDialog.CheckFileExists = true; 
 fDialog.CheckPathExists = true; 
 
 DialogResult res = fDialog.ShowDialog（）; 
 if（res == DialogResult.OK）
 {
 //返回目录的字符串
 return fDialog.FileName.ToString（）; 
} 
 
返回null; 
  

如果我选择图片并完成文件选择，代码可以工作。但是，如果我在任何时候取消进程，我得到例外路径不是法律形式。我不知道我想到哪个部分我可以用 try-catch 来处理这个问题，但是我不是积极的，哪一部分是导致这个问题的？如果我在 ChoosePicture（）方法的调用周围放置一个 try catch ，我至少可以阻止它崩溃程序，但是在fdialogbox中没有选择图片时，仍然会抛出异常。

解决方案

  DialogResult result = fileDialog.ShowDialog（）; 
 if（result == DialogResult.OK）{
 
 //返回目录的字符串
 return fDialog.FileName; 
} 
 
返回null; //不知道如果它们取消
  

，则FileName已经是一个字符串，所以没有需要使用 .ToString（）

编辑：固定缩进

My program has a button which when clicked opens an openfiledialog to choose a picture:

private string ChoosePicture()
{         
    fDialog.Title = "Select Picture";
    fDialog.Filter = "Image Files (*.bmp, *.gif, *.jpg)|*.bmp; *.gif*;*.jpg";
    fDialog.InitialDirectory = "C:";
    fDialog.ShowDialog();

    fDialog.AddExtension = true;
    fDialog.CheckFileExists = true;
    fDialog.CheckPathExists = true;

    //returns a string for the directory
    return fDialog.FileName.ToString();
}

Using a check on the dialogresult box hasn't resolved my issue either:

fDialog.AddExtension = true;
fDialog.CheckFileExists = true;
fDialog.CheckPathExists = true;

DialogResult res = fDialog.ShowDialog();
if (res == DialogResult.OK)
{                
    //returns a string for the directory
    return fDialog.FileName.ToString();
}

return null; 

The code works if I do choose a picture and complete the file selection. However if I cancel the process at any point in between I get the exception "The path is not of a legal form". I am not sure which part I imagine I could take care of this with a try-catch, however I'm not positive which part is causing the issue? If I put a try catch around the call to the ChoosePicture() method, I can at least stop it from crashing the program but the exception is still being thrown when no picture is selected in the fdialogbox.

解决方案

DialogResult result = fileDialog.ShowDialog();
if (result == DialogResult.OK) {

     //returns a string for the directory
     return fDialog.FileName;
}

return null; //not sure what you will return if they cancel

also, FileName is already a string, so no need to use .ToString() on it

EDIT: fixed indenting

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