How to dynamically enable a button in WPF Forms with C#?

Question

Hi, I am new to WPF but not to C#. I am working on a application where I have several buttons and I need to change the state of the buttons based on certain conditions.

For instance, I have this "Add User" button which will be enabled only if the Signed in user is an Admin, if not the button is disabled.

In my XAML, I have the following code for the Add User button:

<UserControl x:Class="sampleProject.controls.controlOptionsMenu"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:sampleProject.controls"
             mc:Ignorable="d" Height="79" Width="800">
    <Grid Background="#FFEDEDED" Height="80">
        <Button x:Name="addUserButton" Width="66" Margin="10,0,0,0" BorderThickness="0,0,0,0" HorizontalAlignment="Left" VerticalAlignment="Center" Height="58" IsEnabled="True">
            <Button.Effect>
                <DropShadowEffect ShadowDepth="3" BlurRadius="5" Color="LightGray"/>
            </Button.Effect>
            <StackPanel Width="62" Height="56">
                <Image Source="/resources/add_user_icon.png" Height="32" Width="32"/>
                <Label Content="Add User" Height="23" Width="60" VerticalAlignment="Center" HorizontalAlignment="Center"/>
            </StackPanel>
        </Button>
    </Grid>
</UserControl>

In my CS code, I have the following condition:

            if(isUserAdmin)
            {
                addUserButton.IsEnabled = true;
            } else
            {
                addUserButton.IsEnabled = false;
            }

When, I execute the button state does not change. Can someone help with this? Thanks In Advance.!

Answer 1

Instead of creating an unused object with new, you should use the control that is already inserted to MainWindow. The XAML of window that contains your user control usually looks like this:

 <local:controlOptionsMenu x:Name="ControlOptionsMenu" . . . />

Specify the x:Name attribute, and use this code:

ControlOptionsMenu.getIfUserIsAdmin( isUserAdmin );

If it does not work, then show details about the usage of your user control in the main window.

Answer 2

Hi,@Lakshmanan B. Welcome to Microsoft Q&A. 

After testing, your cs code could successfully enable or disable the button. Please make sure that your cs code is executed. Below are the test code and steps.

<Grid Background="#FFEDEDED" Height="80">

    <Grid.ColumnDefinitions>

        <ColumnDefinition/>

        <ColumnDefinition/>

    </Grid.ColumnDefinitions>

    <Button IsEnabled="True" Click="addUserButton_Click" x:Name="addUserButton" Width="66" Margin="10,0,0,0" BorderThickness="0,0,0,0" HorizontalAlignment="Left" VerticalAlignment="Center" Height="58" >

        <Button.Effect>

            <DropShadowEffect ShadowDepth="3" BlurRadius="5" Color="LightGray"/>

        </Button.Effect>

        <StackPanel Width="62" Height="56">

            <Image Source="/resources/add_user_icon.png" Height="32" Width="32"/>

            <Label Content="Add User" Height="23" Width="60" VerticalAlignment="Center" HorizontalAlignment="Center"/>

        </StackPanel>

    </Button>

    <Button Grid.Column="1" Width="120" Height="58" Margin="10,0,0,0" Content="Change IsUserAdmin" Click="Button_Click" HorizontalAlignment="Left"></Button>

</Grid>

public partial class controlOptionsMenu : UserControl

{

    public bool isUserAdmin;

    public controlOptionsMenu()

    {

        InitializeComponent();

        isUserAdmin = true;

    }

 

 

    private void addUserButton_Click(object sender, RoutedEventArgs e)

    {

        MessageBox.Show("AAA");

    }

 

    private void Button_Click(object sender, RoutedEventArgs e)

    {

        isUserAdmin = !isUserAdmin;

        if (isUserAdmin)

        {

            addUserButton.IsEnabled = true;

        }

        else

        {

            addUserButton.IsEnabled = false;

        }

    }

}

When you click Change IsUserAdmin button, you could enable or disable the button.When the enabled button is clicked, a pop-up window will pop up

 

Optimization

You could directly bind isUserAdmin to IsEnabled of Button, so that Button could be enabled or disabled in real time according to isUserAdmin. The reference code is as follows.

Change IsEnabled="True" to IsEnabled="{Binding IsUserAdmin}"

<Grid Background="#FFEDEDED" Height="80">

    <Grid.ColumnDefinitions>

        <ColumnDefinition/>

        <ColumnDefinition/>

    </Grid.ColumnDefinitions>

    <Button IsEnabled="{Binding IsUserAdmin}" Click="addUserButton_Click" x:Name="addUserButton" Width="66" Margin="10,0,0,0" BorderThickness="0,0,0,0" HorizontalAlignment="Left" VerticalAlignment="Center" Height="58" >

        <Button.Effect>

            <DropShadowEffect ShadowDepth="3" BlurRadius="5" Color="LightGray"/>

        </Button.Effect>

        <StackPanel Width="62" Height="56">

            <Image Source="/resources/add_user_icon.png " Height="32" Width="32"/>

            <Label Content="Add User" Height="23" Width="60" VerticalAlignment="Center" HorizontalAlignment="Center"/>

        </StackPanel>

    </Button>

    <Button Grid.Column="1" Width="120" Height="58" Margin="10,0,0,0" Content="Change IsUserAdmin" Click="Button_Click" HorizontalAlignment="Left"></Button></Grid>

public partial class controlOptionsMenu : UserControl,INotifyPropertyChanged

{

    private bool isUserAdmin;

    public bool IsUserAdmin

    {

        get { return isUserAdmin; }

        set { isUserAdmin = value; OnPropertyChanged("IsUserAdmin"); }

    }

    public controlOptionsMenu()

    {

        InitializeComponent(); 

        this.DataContext = this;

 

        IsUserAdmin = true;

 

    }

 

    public event PropertyChangedEventHandler PropertyChanged;

 

    public void OnPropertyChanged(string propertyName)

    {

        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

    }

 

    private void addUserButton_Click(object sender, RoutedEventArgs e)

    {

        MessageBox.Show("AAA");

    }

 

    private void Button_Click(object sender, RoutedEventArgs e)

    {

        IsUserAdmin = !IsUserAdmin;

    }

}

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