Store the values ​​of List <List <string >> in a file

The correct Microsoft recommended path is storing data in Settings . The only subtlety - in the Settings not easy to insert non-scalar data.

We act as follows:

1. Go to the project properties, Settings tab.

   

2. We create Settings by default, we put in it property ListOfListsOfStrings . As a type, we cannot select List<List<string>> , therefore we temporarily select just string .

   

3. Close the project (important!), Go to the project directory, open the file Properties\Settings.settings text editor. Find a string like

    <Setting Name="ListOfListsOfStrings" Type="System.String" Scope="User"> 

   we drive the right type

    <Setting Name="ListOfListsOfStrings" Type="System.Collections.Generic.List&lt;System.Collections.Generic.List&lt;System.String&gt;&gt;" Scope="User"> 

   Because we are editing XML, we need to encode < and > like < and > .

   

4. Close the editor, reopen the project. We find the Settings.settings file in the Properties directory in the project, select the Run custom tool from the context menu to regenerate Settings.Designer.cs .

   

5. The project must compile. Add the code that will work with Settings :

    static void Main(string[] args) { var settings = ListListSettings.Properties.Settings.Default; // при первом пробеге тут ничего нет, создаём if (settings.ListOfListsOfStrings == null) { settings.ListOfListsOfStrings = new List<List<string>>() { new List<string>() { "1", "2" }, new List<string>() { "3", "4", "5" } }; settings.Save(); } } 

Everything!

Update: instead of the logic of setting the initial value in Main you can write this very initial value in Settings.settings . To do this, you need to specify the following string as the initial value in the Settings tab:

 <?xml version="1.0" encoding="utf-16"?> <ArrayOfArrayOfString xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <ArrayOfString> <string>1</string> <string>2</string> </ArrayOfString> <ArrayOfString> <string>3</string> <string>4</string> <string>5</string> </ArrayOfString> </ArrayOfArrayOfString> 

It needs to be copied into the Value input field, rather than trying to manually write to the Settings.settings file, because the < and > values ​​in the file need to be changed to < and > . It should turn out something like this:

Where to get such a tricky line? Do not invent it yourself? In fact, it can be found by adding this code:

 var sample = new List<List<string>>() // это тот список, который мы раньше { // записывали в settings.ListOfListsOfStrings new List<string>() { "1", "2" }, new List<string>() { "3", "4", "5" } }; var xs = new XmlSerializer(sample.GetType()); using (var sw = new StringWriter()) { xs.Serialize(sw, sample); var serialized = sw.ToString(); // (*) } 

At the point marked with an asterisk, look at the value of the serialized variable through the debugger - there will be exactly what you need:

Given the changes, the program code is simplified to this:

 static void Main(string[] args) { var settings = ListListSettings.Properties.Settings.Default; var listOfList = settings.ListOfListsOfStrings; } 

@Pavel Mayorov, thanks for the help in the comments.