如何将新列表项添加到列表 <string> 在settings.settings中

Question

I am trying to add new list item to settings.settings file. I have modified my settings.settings file as below

and on button click i have the following code:

 private void button7_Click(object sender, EventArgs e)
        {
string tempConString = "server='.\sqlexpress';database='somedatabasename';Trusted_Connection=Yes;";
 Properties.Settings.Default.connectionString.Add(tempConString);
                                Properties.Settings.Default.Save();
}

i am getting NullReferenceException with message Object reference not set to an instance of an object.

I want to save multiple strings to Properties.Settings.Default.connectionString

Answer 1

To achieve desired behavior you should follow the Accepted Answer of the post . I don't understand why a wrong answer is so upvoted.

Never the less, just pick System.Collection.Specialized.StringCollection from Type DropDown and insert your values from new lines. And where you want to use it do something like this:

Console.WriteLine(Settings.Default.test.Cast<string>().ToList().FirstOrDefault());

Everything was in that post, to be honest.

Follow instructions from http://csharphelper.com/blog/2011/08/use-a-setting-that-contains-a-string-collection-in-c/