Wpf netframeworkcore 3.1 MVVM visibility

Question

0.00/5 (No votes)

See more:

I try to hide an object via the properties of another object I do not know what the problem is, but it does not work

Binding code

XML

<StackPanel Orientation="Horizontal">
    <Grid Margin="25,0,0,0" HorizontalAlignment="Center">
        <TextBlock
            Text="اسم المستخدم" 
            FontWeight="Light"
            FontSize="18"
            Foreground="White"
            Background="Transparent"
            Width="230"
            Opacity="0.5"
            Height="28"
            Visibility="{Binding Path=VisbTbU , Mode=TwoWay}"/>
        <TextBox 
            FontFamily="Helvetica"
            FontWeight="Light"
            FontSize="18"
            HorizontalAlignment="Center"
            Foreground="White"
            Background="Transparent"
            BorderThickness="0"
            Width="235"
            HorizontalContentAlignment="Left"
            Opacity="0.5"
            Height="25"
            Text="{Binding UserLog}"
        />
    </Grid>
    <iconPacks:PackIconMaterial 
        Kind="Account"
        VerticalAlignment="Center"
        HorizontalAlignment="Center"
        Foreground="White"
    />
</StackPanel>

viewmodel code

C#

public VmWinLogin()
{
    VisbTbp = Visibility.Visible;
    VisbTbp = Visibility.Visible;
    UserLog = "";
    UserPass = "";
}

private Visibility _VisbTbU ;

public Visibility VisbTbU
{
    get => _VisbTbU;
    set
    {
        _VisbTbU = value;
       // OnPropertyChanging();
       OnPropertyChanging();
    }
}


private string _UserLog ;

public string UserLog
{
    get => _UserLog .Trim();
    set
    {
        _UserLog = value .Trim();
        OnPropertyChanging();
        if (_UserLog == "")
        {
            VisbTbU = Visibility.Visible;
        }
        else
        {
            VisbTbU = Visibility.Hidden;
        }
    }
}

basemodel code

C#

public event PropertyChangingEventHandler PropertyChanging;

public event PropertyChangedEventHandler PropertyChanged;

[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanging([CallerMemberName] string propertyName = null)
{
    PropertyChanging?.Invoke(this, new PropertyChangingEventArgs(propertyName));
}

What I have tried:

I tried to follow the implementation to make sure the value of the property did not change and I found that it changed, but there is no effect on the object.

Posted 21-May-20 11:03am

khaled_basher

Updated 22-May-20 0:29am

Richard Deeming

v2

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

phil.o · Answer 1 · 2020-05-22T00:30:00

Solution 1

Technically, OnPropertyChanging can be eventually called before corresponding property is modified. Once the property has been modified, then OnPropertyChanged has to be called. You are only calling OnPropertyChanging after the modification, so there is a great chance that the system never catches the PropertyChanged event.

Posted 22-May-20 0:30am

phil.o

Comments

khaled_basher 22-May-20 10:47am

nvoke PropertyChanged It also did not work

public event PropertyChangedEventHandler PropertyChanged;

protected void OnPropertyChanged([CallerMemberName] string propertyName = null) { VerifyPropertyName(propertyName); PropertyChanged?.Invoke(this,new PropertyChangedEventArgs(propertyName)); }

phil.o 22-May-20 11:06am

Did you really change the code in the VisbTbU setter as well?