WPF checkbox binding don't work

Question

I've updated the question with my xaml code. The problem is the listview, which is under a popup tag. Thank everyone for your help.

Xaml code

<Popup Name="black_list_seting" 
                   StaysOpen="False"
              AllowsTransparency="True"
                   Closed="emoj_closed"
    PlacementTarget ="{Binding ElementName=emj_btn}" 
    Placement="Left">
                <Border  HorizontalAlignment="Left" VerticalAlignment="Top"  BorderBrush="Black" BorderThickness="0.5">
                    <Grid x:Name="black_list_grid" Width="270" Height="238" Background="White" ScrollViewer.VerticalScrollBarVisibility="Visible"  >

                        <ListView  x:Name="black_listview" HorizontalAlignment="Left" Height="219"  Margin="10,10,0,0" VerticalAlignment="Top" Width="254" >

                            <ListView.View>

                                <GridView >

                                    <GridView.ColumnHeaderTemplate>
                                        <DataTemplate >
                                            <DockPanel Margin="-40,0,0,0">

                                                <TextBlock FontSize="12" HorizontalAlignment="Left" Foreground="#383e4b">
                                                    <TextBlock.Text>
                                                        <Binding/>
                                                    </TextBlock.Text>
                                                </TextBlock>
                                            </DockPanel>
                                        </DataTemplate>
                                    </GridView.ColumnHeaderTemplate>

                                    <GridViewColumn Header="name"
                DisplayMemberBinding="{Binding user_name}"
                Width="100"/>
                                    <GridViewColumn Header="ignore"
                Width="100">

                                        <GridViewColumn.CellTemplate>
                                            <DataTemplate>
                                                <CheckBox DataContext="{Binding check_key}"  IsChecked="{Binding IsSelected}" Checked="black_list_item_fn"></CheckBox>
                                            </DataTemplate>

                                        </GridViewColumn.CellTemplate>

                                    </GridViewColumn>


                                </GridView>
                            </ListView.View>






                        </ListView>



                    </Grid>
                </Border>
            </Popup>

Code behind

    public class contact_user_data
    {

        public string user_name { get; set; }
        public string user_key { get; set; }
        public string check_key { get; set; }
        public string head_url { get; set; }
        private bool isSelected;
        private string name;

        public bool IsSelected { get; set; }
    }

List view Itemssource definition code

         var source = global_var.black_list_soruce[md5];
        if (source != black_listview.ItemsSource)
        {

        }
        black_listview.ItemsSource = null;
        //  black_listview.Items.Clear();
        black_listview.ItemsSource = source;

        black_list_seting.IsOpen = true;

No matter how I define the check box binding, it has been unchecked.

Please help me !! I spent three days researching this problem

You bind the **DataContext** of CheckBox to check_key property and **IsChecked** to IsSelected property!!! it's not clear — Amine, May 02 '16 at 00:07
hello @Amine I also need to provide any information so that you to understanding it? — 張願麗, May 02 '16 at 00:16

score 1 · Answer 1 · edited May 23 '17 at 11:52

looking at next expression:

<CheckBox DataContext="{Binding check_key}"  IsChecked="{Binding IsSelected}" Checked="black_list_item_fn"></CheckBox>

I can say you that the binding can't work. Please pay attention on a small explanation:

A DataContext="{Binding check_key}" - defines the data context of the checkbox.
A IsChecked="{Binding IsSelected}" - say that the checked/unchecked state is defined by the IsSelected property which is existing in the DataContext. Since the check_key property of the contact_user_data class is a string and the IsSelected is not a member of the string class, we have a binding expression that destruct the binding process, and nothing is working here(the check box wasn't bound because of binding expression).
In addition you should use an INPC here to make a binding to work on the fly.

My suggestion is; try to remove the DataContext="{Binding check_key}" from your checkbox declaration, then the framework will find the binding path and the state will be defined at least in first time(since the INPC is not implemented- interesting article concerning the INPC must).

Example

<CheckBox IsChecked="{Binding IsSelected}" Checked="black_list_item_fn"/>

Regards.

WPF checkbox binding don't work

1 Answers1