How can I prevent an exception when I cancel an openfiledialog?

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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.

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

How to prevent an exception when canceling an OpenFileDialog , When the user cancels the dialog, your getFileName function returns an empty string. Therefore, you get an exception when you try to load the image from a path  I'm trying to implement an OpenFileDialog box, its works fine except if I choose to click cancel then program throws an error, saying that file can't be found, which confuses me cause I didnt select a file. The following is the code. how I can implement the cancel button?

Check the dialog result and act accordingly:

private string ChoosePicture()
{         

        fDialog.Title = "Select Picture";
        fDialog.Filter = "Image Files (*.bmp, *.gif, *.jpg)|*.bmp; *.gif*;*.jpg";
        fDialog.InitialDirectory = "C:";
        DialogResult res = fDialog.ShowDialog();

        if(res == DialogResult.OK)
        {
           fDialog.AddExtension = true;
           fDialog.CheckFileExists = true;
           fDialog.CheckPathExists = true;

           //returns a string for the directory
           return fDialog.FileName.ToString();
        }            
        else
        {
           return null; // or something
        }
}

C# How to prevent an exception when canceling an OpenFileDialog , C# How to prevent an exception when canceling an OpenFileDialog? Hey,. I am having a problem when I click cancel on an openfiledialog in c#, it throws an  when i gave the above code.. now OpenFileDialog is coming two time.. when i cancel the OpenFileDialog its again opening.. – Stacy Kebler Oct 20 '14 at 17:56 its because.. in button4_Click, there is image_print() .. and also. string s = image_print() .

Test to see if a file was selected:

   fDialog.ShowDialog();
   if (!string.IsNullOrEmpty(fDialog.FileName))
   {
        fDialog.AddExtension = true;
        fDialog.CheckFileExists = true;
        fDialog.CheckPathExists = true;

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

FileDialog.Filter Property (System.Windows.Forms), The file filtering options available in the dialog box. Exceptions. ArgumentException. Filter format is invalid. Examples. The following code example uses the  When you look closely, you can also spot some differences between the contents of the dialogs. My conclusion is that Microsoft completely replaced the standard dialog in Visual Studio to give it this capability. My solution or something similar will be as close as you can get, unless you’re willing to code your own from scratch.

DialogResult dresult=fDialog.ShowDialog();

Check if dresult==DialogResult.Ok and only after proceed with file operations.

OpenFileDialog.ReadOnlyChecked Property (System.Windows , This example displays the OpenFileDialog box with the ShowReadOnly property StackTrace ); } catch (Exception ex) { // Could not load the image - probably  Hi . I am using Openfiledialog box using VB.net. Here is my coding . i hope this will useful to you 'Main code. You can call Fileopen() whereever you want

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; 

Now it will work !

We should add properties to the dialogbox before its actually been shown. So when it opens, it will have all these properties when you open them for the first time.

Edit :okay you have added to the designer by the toolbox already and its by default all of these options. but if some add from code. it should be always before its being shown. I will leave this here. so that someone who does this

this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();

in code, will know that they should do these property addition before showing the dialog. Again, these true values are by default so unless u have mentioned false before elsewhere and making it true here.

C# OpenFileDialog Example, Use the OpenFileDialog control in Windows Forms to enable the selection of a file. We also handle exceptions, preventing some errors related to file system  There are two problems to deal with: 1. The dialog must be run on a separate thread. 2. The dialog must be modal for the CORRECT INSTANCE of the SAP client window. With my item events I invoke the dialog with the following code example for an excel file. I was using the try/catch for debugging purposes.

Learning Java Through Games, If an exception is generated, then the try block will stop executing and the point of if the code goes through the whole try block without an exception being raised, called JFileChooser that displays the usual open file dialog; see Figure 13.1. be pressed in order to select a file. A cancel. Exception Handling and Files 299. Examples. The following code example creates an OpenFileDialog, sets several properties to define the file extension filter and dialog behavior, and displays the dialog box using the CommonDialog.ShowDialog method.

Computing with C# and the .NET Framework, Inside the catch block we can display the exception to show which exception occurred and The Close method releases resources back to the operating system. The OpenFileDialog, Save FileDialog, and FontLialog classes in the System. A(n) _____ is an object that can hold a group of values that must all be the same data type. scores = new int[12]; Which one of the following assignment statements associates an int array, that can hold 12

VB .NET in 60 Minutes a Day, Title = “Locate Image” 'Display the Open File dialog: OpenFileDialog1. that could be checked prior to the assignment to avoid the exception altogether. 29. After you locate an image and close the OpenFileDialog box, the active child form​  Example: Open a file from a filtered selection with OpenFile. The following example uses the Button control's Click event handler to open the OpenFileDialog with a filter that shows only text files. After the user chooses a text file and selects OK, the OpenFile method is used to open the file in Notepad.

Comments
  • wrap your code for the Dialogresult around an If else statement
  • This happens because you ignore the return value of ShowDialog(). Could be the bad indenting too.
  • just add your dialogbox constraints before actually showing the dialog. after that its all done and this checking simply doesn't matter
  • unless you are setting them in the designer, this setting actually doesn't matter to the control when used for the first time.
  • it sounds like you need to check the value being returned from the ChoosePicture() method before you process any further. If the method returns an empty string or null, don't proceed any further. Show the code that is calling the ChoosePicture() method
  • I tried your result, still throws the error : "The path is not of a legal form"
  • at which line are you getting the error. If you cancel out of the dialog, it should never drop into the block where it does anything with the FileName property. Set a break point on the if statement and let us know what the value of result is when you click Cancel
  • I just took your original code and tried it, I do not get the error even when trying to get the filename, it is an empty string. Is your error happening after you return the value from your ChoosePicture() method?
  • It occurs somewhere else where I was basing other values off of the returned value. Your code is good, I should have looked at a larger scope. Thank you.
  • keep the properties of the file dialog before showing the dialog. this way of adding properties to the control doesn't make any sense when it happens for the first time
  • I tried your result, still throws the error : "The path is not of a legal form"
  • It occurs somewhere else where I was basing other values off of the returned value. Your code is good, I should have looked at a larger scope. Thank you.