How I can call a Init() function from my ViewModel?

Question

How I can call a Init() function from my ViewModel?

Markus Freitag 3,791

Hello, How I can call a Init() function from my ViewModel?

<Grid DataContext="{StaticResource vm}">
What is different with StaticResource and without?

I need without static, then the list works not.

public partial class MainWindow : Window  
    {  
        public MainWindow()  
        {  
            InitializeComponent();  
  
  
            //DataContext.  
            ((ViewModel)DataContext).Init();  
        }     
     
    }

Not possible, why?

Peter Fleischer (former MVP) 19,351 Reputation points

2020-07-14T19:10:58.27+00:00

Hi Markus, include call Init method in ctor of ViewModel. Your code ist a mixture of CodeBehind and MVVM.

<Grid DataContext="{StaticResource vm}">
What is different with StaticResource and without?

The DataContext is necessary for binding.
Markus Freitag 3,791 Reputation points

2020-07-14T19:42:10.547+00:00

Hi Peter,

<Grid DataContext="{StaticResource vm}">

I use this
<Grid> only Grid!!!

and (Window.DataContext) See picture 1
Then the Delete button inside our list was not working.
Why you use {StaticResource vm} ?

Your code ist a mixture of CodeBehind and MVVM.

What is wrong?
I want to start the application and fill our list without press the LOAD button.

How can I do it? I want to fill a empty list. Not more.
DaisyTian-1203 11,651 Reputation points Moderator

2020-07-15T06:00:46.247+00:00
As PeterFleischer said, you mixes up two way of bingding data. If you use MVVM to bind data in view, you can do like below code shown.When the View loads, the data will be bind automatically, it is no need to use DataContext or init () in codebind.

<Page.Resources> <local:ViewModel x:Key="MyVM"></local:ViewModel> </ Page.Resources> <Grid DataContext="{StaticResource MyVM}"> <TextBox Name="txtName" Width="200" HorizontalAlignment="Left" VerticalAlignment="Center" Text="{Binding Name}" /> </Grid>
Markus Freitag 3,791 Reputation points

2020-07-15T12:20:56.163+00:00
OK,
public partial class MainWindow : Window
{
public MyLogger Log;

public MainWindow() { InitializeComponent();

.....
ViewModel
Others class
So I need one Logger, how I can make access to the logger in all classes, global?

How I can get access from my ViewModel zu the members of MainWindow?
DaisyTian-1203 11,651 Reputation points Moderator

2020-07-16T08:19:25.04+00:00

You can use any class in all classes if the used class is under your project namespace. If you want to use it directly, you can make it to static.For the log issue, how about using log4net to create log?

Answer accepted by question author

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Peter Fleischer (former MVP) 19,351 Reputation points

2020-07-14T19:10:58.27+00:00

Hi Markus, include call Init method in ctor of ViewModel. Your code ist a mixture of CodeBehind and MVVM.

<Grid DataContext="{StaticResource vm}">
What is different with StaticResource and without?

The DataContext is necessary for binding.
Markus Freitag 3,791 Reputation points

2020-07-14T19:42:10.547+00:00

Hi Peter,

<Grid DataContext="{StaticResource vm}">

I use this
<Grid> only Grid!!!

and (Window.DataContext) See picture 1
Then the Delete button inside our list was not working.
Why you use {StaticResource vm} ?

Your code ist a mixture of CodeBehind and MVVM.

What is wrong?
I want to start the application and fill our list without press the LOAD button.

How can I do it? I want to fill a empty list. Not more.
DaisyTian-1203 11,651 Reputation points Moderator

2020-07-15T06:00:46.247+00:00

As PeterFleischer said, you mixes up two way of bingding data. If you use MVVM to bind data in view, you can do like below code shown.When the View loads, the data will be bind automatically, it is no need to use DataContext or init () in codebind.

<Page.Resources> <local:ViewModel x:Key="MyVM"></local:ViewModel> </ Page.Resources> <Grid DataContext="{StaticResource MyVM}"> <TextBox Name="txtName" Width="200" HorizontalAlignment="Left" VerticalAlignment="Center" Text="{Binding Name}" /> </Grid>
Markus Freitag 3,791 Reputation points

2020-07-15T12:20:56.163+00:00

OK,
public partial class MainWindow : Window
{
public MyLogger Log;

public MainWindow() { InitializeComponent();

.....
ViewModel
Others class
So I need one Logger, how I can make access to the logger in all classes, global?

How I can get access from my ViewModel zu the members of MainWindow?
DaisyTian-1203 11,651 Reputation points Moderator

2020-07-16T08:19:25.04+00:00

You can use any class in all classes if the used class is under your project namespace. If you want to use it directly, you can make it to static.For the log issue, how about using log4net to create log?

Answer 1

Peter Fleischer (former MVP) 19,351

There are various ways to call a method from the code-behind.

approach:

public partial class MainWindow : Window
{
  public MainWindow()
  {
    ViewModel vm = new ViewModel();
    this.DataContext = vm;
    InitializeComponent();
    vm.Init();
  }
}

approach:

public MainWindow()
{
  this.Resources.Add("vm", new ViewModel());
  this.Loaded += MainWindow_Loaded;
  InitializeComponent();
}

private void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
  var vm = (ViewModel)(this.Resources["vm"]);
  vm.Init();
}

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How I can call a Init() function from my ViewModel?

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