C# Properties.Settings.Default

Question

How to ensure that retrieving value from Properties.Settings.Default exists? For example, when I use this code:

folderBrowserDialog1.SelectedPath = (string)Properties.Settings.Default["SelectedPath"];

and value SelectedPath does not exist, I get the followng exception:

System.Configuration.SettingsPropertyNotFoundException' occurred in System.dll

How can I avoid this exception?

possible duplicate of [C#: How to make sure a settings variable exists before attempting to use it from another assembly?](http://stackoverflow.com/questions/4647796/c-how-to-make-sure-a-settings-variable-exists-before-attempting-to-use-it-from) — B.K., Nov 09 '14 at 17:37
I saw this question but I didn't understand how to use "CommonSettings.Default.ContainsKey(str)". How to get CommonSettings? — Alex Zhulin, Nov 09 '14 at 17:47
It isn't very clear why you'd write code like this. Use Properties.Settings.Default.SelectedPath and the compiler will tell you that you got it wrong. Which is the point of using the settings designer. — Hans Passant, Nov 09 '14 at 18:13
Thank you. I wanted to do all things in runtime, like I used with registry in early times. But it seems that I don't have another way than use settings designer — Alex Zhulin, Nov 09 '14 at 19:08

score 3 · Answer 1 · answered Dec 04 '15 at 11:21

3

Here is a method to check for the existence of a key:

    public static bool PropertiesHasKey(string key)
    {
        foreach (SettingsProperty sp in Properties.Settings.Default.Properties)
        {
            if (sp.Name == key)
            {
                return true;
            }
        }
        return false;
    }

answered Dec 04 '15 at 11:21

Paul Richards

1,181
1
10
29

While the method shown below works, it does so at the cost of an exception. OTOH, the method shown above avoids raising exceptions. – David A. Gray Aug 29 '18 at 04:53

score 2 · Accepted Answer · answered Nov 09 '14 at 17:39

Unless that collection provides a method to check whether a given key exists then you will have to wrap the code in a try..catch block.

 try{
     folderBrowserDialog1.SelectedPath = (string)Properties.Settings.Default["SelectedPath"];
 }catch(System.Configuration.SettingsPropertyNotFoundException)
 {
     folderBrowserDialog1.SelectedPath = "";  // or whatever is appropriate in your case
 }

If the Default property implements the IDictionary interface you can use the ContainsKey method to test that the given key exists before trying to access it, like so:

 if(Properties.Settings.Default.ContainsKey("SelectedPath"))
 {
     folderBrowserDialog1.SelectedPath = (string)Properties.Settings.Default["SelectedPath"];
 }else{
     folderBrowserDialog1.SelectedPath = ""; // or whatever else is appropriate in your case
 }

Arsalan · Answer 3 · 2014-11-09T18:04:13.603

try this:(our friend 'Mike Dinescu' mention that with no details - Edit: he has provided details now)

try
{
    folderBrowserDialog1.SelectedPath = 
     (string)Properties.Settings.Default["SelectedPath"]
}
catch(System.Configuration.SettingsPropertyNotFoundException e)
{
    MessageBox.Show(e.Message); // or anything you want
}
catch(Exception e)
{
    //if any exception but above one occurs this part will execute
}

I hope this solution solve your problem :)

Edit : Or without using try catch :

if(!String.IsNullOrEmpty((string)Properties.Settings.Default["SelectedPath"]))
{
   folderBrowserDialog1.SelectedPath = 
         (string)Properties.Settings.Default["SelectedPath"]
}

Thank you, but is there any way without using try ... catch(System.Configuration.SettingsPropertyNotFoundException e)? — Alex Zhulin, Nov 09 '14 at 17:50

score 0 · Answer 4 · answered May 31 '20 at 14:18

you can set default null value for the variable . add this code to Settings.Designer.cs file :

[UserScopedSetting]
[DebuggerNonUserCode]
[DefaultSettingValue(null)] // <-- set default value
public string test1
{
    get
    {
        return (string)this[nameof(test1)];
    }
    set
    {
        this[nameof(test1)] = (object)value;
    }
}

then check :

if (Properties.Settings.Default.test1 != null)

C# Properties.Settings.Default

4 Answers4