WPF Application using a global variable

Question

I created a WPF application in c# with 3 different windows, Home.xaml, Name.xaml, Config.xaml. I want to declare a variable in Home.xaml.cs that I

Answer 1

There are two different things you can do here (among others; these are just the two that come to mind first).

1. You could make the variable static on Home.xaml.cs

   public static string Foo = "";
   

2. You could just pass in the variable to all three forms.

I would go with #2, myself, and if necessary create a separate class that contains the data I need. Then each class would have access to the data.

Answer 2

You can use a static property:

public static class ConfigClass()
{
    public static int MyProperty { get; set; }
}

Edit:

The idea here is create a class that you holds all "common data", typically configurations. Of course, you can use any class but suggest you to use a static class. You can access this property like this:

Console.Write(ConfigClass.MyProperty)

Answer 3

The proper way, especially if you ever want to move to XBAPP, is to store it in

Application.Current.Properties

which is a Dictionary object.

Answer 4

App.xaml:

<Application x:Class="WpfTutorialSamples.App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:sys="clr-namespace:System;assembly=mscorlib"
         StartupUri="WPF application/ResourcesFromCodeBehindSample.xaml">
<Application.Resources>
    <sys:String x:Key="strApp">Hello, Application world!</sys:String>
</Application.Resources>

Code-behind:

Application.Current.FindResource("strApp").ToString()

Answer 5

As other people mentioned before either use App.Current.Properties or create a static class. I am here to provide an example for those who need more guidance with the static class.

1. Add a new Class

Right-click your project name in your solution explorer Add > New Item choose Class give it a name (I usually name it GLOBALS)

2. What that cs file should look like

using System;

namespace ProjectName
{
    public static class GLOBALS
    {
        public static string Variable1 { get; set; }
        public static int Variable2 { get; set; }
        public static MyObject Variable3 { get; set; }
    }
}

3. Add references into .cs files where you intend to use those variables

using ProjectName

4. We're done. Use it. Examples:

GLOBALS.Variable1 = "MyName"
Console.Write(GLOBALS.Variable1)
GLOBALS.Variable2 = 100;
GLOBALS.Variable2 += 20;
GLOBALS.Variable3 = new MyObject();
GLOBALS.Variable3.MyFunction();

On a side note, do notice that using the static class as global variables in c# is considered a bad practice (that's why there is no official implementation for globals), but I consider it a shortcut for when I am too lazy haha. It should not be used in the professional environment.

Answer 6

To avoid having to pass around values between windows and usercontrols, or creating a static class to duplicate existing functionality within WPF, you could use:

• setting: App.Current.Properties["NameOfProperty"] = 5;
• getting: string myProperty = App.Current.Properties["NameOfProperty"];

This was mentioned above, but the syntax was a little off.

This provides global variables within your application, accessible from any code running within it.