Combobox showing error "Binding expression path error"

Question

I have two combobox which are currently binded to the user model. The first combobox supposed to show the current userRole value before clicking on the combobox. The other combobox supposed to show the userStatus either 1 or 0. Now the second combobox is not displaying any value. However the first combobox is displaying the value once its clicked only.

Here is the xaml code:

<StackPanel Orientation="Horizontal">
<TextBlock FontSize="12" Text="User Role: " VerticalAlignment="Center" />
<ComboBox x:Name="cbUserRole" FlowDirection="LeftToRight" FontSize="16" Foreground="MidnightBlue" HorizontalAlignment="Stretch" VerticalAlignment="Center" Loaded="cbUserRole_Loaded" SelectedItem="{Binding UserRole, Mode=TwoWay" />
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock FontSize="12" Text="User Status: " VerticalAlignment="Center" />
<ComboBox x:Name="cbUserStatus" FlowDirection="LeftToRight" FontSize="16" Foreground="MidnightBlue" HorizontalAlignment="Stretch" VerticalAlignment="Center" SelectedIndex="{Binding UserStatus, Converter={StaticResource boolToIndexConverter}}" />
</StackPanel>

Here is my converter code:

 public class BoolToIndexConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return ((bool)value == true) ? 0 : 1;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return ((int)value == 0) ? true : false;
    }
}

The code above is refered from this link:

Here is my User model code:

private string userrole;


    public string UserRole
    {
        get { return userrole; }
        set
        {
            userrole = value;
            OnPropertyChanged("UserRole");
        }
    }

private bool userstatus;


    public bool UserStatus
    {
        get { return userstatus; }
        set
        {
            userstatus = value;
            OnPropertyChanged("UserStatus");
        }
    }

How can i fix this problems? I did search and tried from different blogs but its not working for me.

I believe that DataContext is incorrect for the block of XAML you provided. Please post classname of your viewModel and full error message. BindingExpression path error: 'XXX' property not found on 'object' 'YYYViewModel' — Access Denied, Sep 06 '18 at 03:14
The classname for my viewModel is **UserViewModel** and the error message I am getting now is **System.Windows.Data Error: 40 : BindingExpression path error: 'ADMIN_USER' property not found on 'object' ''User' (HashCode=50791566)'. BindingExpression:Path=NPI_USER; DataItem='User' (HashCode=50791566); target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String')** — anonymous_apple, Sep 06 '18 at 03:27
@AccessDenied Isnt it I supposed to Bind the properties from my User model? — anonymous_apple, Sep 06 '18 at 03:29
@AccessDenied I have posted my whole xaml code for you. Here is the link: https://pastebin.com/5UP5StNP — anonymous_apple, Sep 06 '18 at 03:37
Post your code behind since I don't see where you set context. — Access Denied, Sep 06 '18 at 03:41
@AccessDenied sorry you mean you want my view model code or the xaml behind code? — anonymous_apple, Sep 06 '18 at 03:44
@AccessDenied can we move the discussion to chat? if yes please move it since I dont have enough points to move to chat — anonymous_apple, Sep 06 '18 at 04:09
@AccessDenied here is the [link](https://github.com/raaj5671/wpf/tree/development/shopfloorcs) the file u should view now is view_user.xaml and the model and view model file — anonymous_apple, Sep 06 '18 at 04:37
@anonynous_apple see my answer, don't forget to upvote and mark as answer if it helps. — Access Denied, Sep 06 '18 at 05:55

Access Denied · Accepted Answer · 2018-09-06T05:53:03.273

0

The problem is that your combobox's DataContext is User, but you need to set ItemsSource from DataGrid's datacontext. In order to do that you need to use the following syntax:

 <ComboBox 
ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType={x:Type DataGrid}}, Path=DataContext.Users}" 
                                          x:Name="cbUserRole" FlowDirection="LeftToRight" FontSize="16" Foreground="MidnightBlue" HorizontalAlignment="Stretch" VerticalAlignment="Center" 
                                          SelectedItem="{Binding UserRole,Mode=TwoWay}"></ComboBox>

And Remove Loaded handler.

You can also use <DataGrid DataContext="{StaticResource uvm}" instead of codebehind code:

var userList = new UserViewModel().Users;
userDataGrid.ItemsSource = userList;

You don't have ItemsSource for your Status Combobox. I think you should add collection of statuses to UserViewModel and bind it like in the example above.

edited Sep 06 '18 at 05:53

answered Sep 06 '18 at 05:42

Access Denied

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`RelativeSource={RelativeSource FindAncestor,AncestorType={x:Type DataGrid}},` the following code is populating the whole user roles, I dont want that for my case. In my database there is only 4 user roles. – anonymous_apple Sep 06 '18 at 07:05
@anonymous_apple Make another property instead of getUserRoles() create UserRoles property in your view model. – Access Denied Sep 06 '18 at 07:19
and change xaml in my sample to Path=DataContext.UserRoles – Access Denied Sep 06 '18 at 07:20
**I think you should add collection of statuses to UserViewModel and bind it like in the example above.** Based on the bold words, I am not getting the idea....The status is either Enable or Disable only. How can I achieve that? If u see my code I created a IValueConverter but its not working... – anonymous_apple Sep 06 '18 at 07:25
You have combobox and no items in it, maybe you should use checkbox? – Access Denied Sep 06 '18 at 07:26

Combobox showing error "Binding expression path error"

1 Answers1