ColumnDefinition MinWidth=744 - WPF Discussion Boards

SledgeHammer014-Nov-11 8:55

4-Nov-11 8:55

You can't bind to the VM directly. ElementName needs a UIElement... thats why I mentioned that you have to have a Name tag on your top level window Smile | :)

. So its either going to be something like:

<Window Name=myWindow...>

<ComboBox DataContext="{Binding ElementName=QueryViewModel, Path=DataContext}" ... >

or maybe:

<UserControl Name=myWindow...>

Remember, your Window or UserControl DataContext points to your VM. You need to reference that one. I *think* you can also use the DataContext from the DataGrid, so something like:

<ComboBox DataContext="{Binding ElementName=grdItems, Path=DataContext}" ... >

One of those should work Smile | :)

Kevin Marois4-Nov-11 9:01

4-Nov-11 9:01

I dunno. I get what's supposed to happen, I just can't make it work. I'm really starting to think about a different approach.

Everything makes sense in someone's mind

SledgeHammer014-Nov-11 10:34

4-Nov-11 10:34

Should work as long as your are binding to a <b>UIElement</b> that has its DataContext set properly. We already the top level window has its DataContext set to your VM, so you must point your ComboBox's DataContext to the VM if you want to reference properties from the VM.

You might to post your full XAML and what error messages you are getting. Also, try turning on verbose WPF debugging.

Kevin Marois6-Nov-11 7:02

6-Nov-11 7:02

Here's the XAML as it is now:

<DataGrid x:Name="grdItems"
            Grid.Row="4"
            Grid.Column="0"
            Grid.ColumnSpan="2"
            AutoGenerateColumns="False"
            ItemsSource="{Binding SearchItems}"
            Visibility="{Binding GridVisible, Converter={StaticResource visibilityConverter}}"
            Margin="5">

    <DataGrid.Columns>
        <DataGridTemplateColumn Header="Search Terms"
                                Width="*">
            <DataGridTemplateColumn.CellEditingTemplate>
                <DataTemplate>
                    <ComboBox x:Name="cboBOMs"
                                Height="22" 
                                DataContext="{Binding ElementName=QueryView, Path=DataContext}"
                                IsEditable="True"
                                ItemsSource="{Binding BOMs}"
                                SelectedItem="{Binding SelectedBOMItem}"></ComboBox>
                </DataTemplate>
            </DataGridTemplateColumn.CellEditingTemplate>
        </DataGridTemplateColumn>
        <DataGridTextColumn Header="Quantity" 
                            Binding="{Binding Quantity}"
                            Width="100">
        </DataGridTextColumn>
    </DataGrid.Columns>

</DataGrid>

I don't understand what's going on because this code is in QueryView.xaml. You can see the combo is looking for the DC on QueryView.

The output window shows the error:

Cannot find source for binding with reference 'ElementName=QueryView'. BindingExpression:Path=DataContext; DataItem=null; target element is 'ComboBox' (Name='cboBOMs'); target property is 'DataContext' (type 'Object')

This appeaars to be right. I don't get it and I'm tired of screwing with it. if the DB wasn't so damn big I'd post the entire app on my site and ask for more help. I'm fairly frustrated at this point.

Everything makes sense in someone's mind

SledgeHammer017-Nov-11 6:46

7-Nov-11 6:46

How about using grdItems for ElementName? What type is QueryView? Seems like this should be working to me too.

Abhinav S3-Nov-11 17:13

ColumnDefinition MinWidth=744

3-Nov-11 17:13

Within a DataGrid, you need to use a DataGridComboBoxColumn in your template.
Here[^] is some code that might help you out.

indian1432-Nov-11 14:57

indian143

2-Nov-11 14:57

Hi All,

I have a parent grid in one xaml file in which we are loading the different regions. For that grid the column definitions are defined in the following way

<Grid.ColumnDefinitions>
                <ColumnDefinition Width="10" />
                <ColumnDefinition MinWidth="744" Width="*"  />           
               <ColumnDefinition Width="10" />
            </Grid.ColumnDefinitions>

in the second column we are loading a different user control, is there any way to get the MinWidth=744 value in the child user control dynamically through code.

I want to get that value what we set here in the user control which will be loaded in that second column. I have hard coded it but I want to use it in the following way in a different user control (means different xaml file)

if (assignmentOperator.ActualWidth > 744) //Checks if the LayoutGrid size is >= to 744 
            {
                double temp = gridFilterCriteria.ActualWidth; //Assigns gridFilterCriteria.ActualWidth to temp value
                this.textBlockCriteria.Width = temp * (0.99);//                                        
            }

here instead of 744 I want to set this if condition dynamically like
if (assignmentOperator.ActualWidth > <here i="" want="" some="" property="" which="" would="" give="" me="" this="" value="">)

can anybody help me please, I need it friends. Please help me yaar.

Thanks & Regards,

Abdul Aleem Mohammad
St Louis MO - USA

Re: ColumnDefinition MinWidth=744

Abhinav S2-Nov-11 18:04

Trying To Shutdown WPF App - Application.Current is null

2-Nov-11 18:04

You can loop over the set of grids in your xaml, get the appropriate control (access the children and get the column name) and then set its MinWidth value to what you need. This is not the neatest way to do this, but will get the width set.

Kevin Marois2-Nov-11 6:55

Re: Trying To Shutdown WPF App - Application.Current is null

2-Nov-11 6:55

Here's the code

private void login()
{
    Login loginView = new Login();
    loginView.ShowDialog();

    if (MyAppEngine.CurrentUser == null)
    {
        Application.Current.Shutdown();
    }
}

The app is crashing with a null object ref exception on the Shutdown line when I fail to log in. Why would Application.Current ever be null??

Everything makes sense in someone's mind

SledgeHammer012-Nov-11 7:49

Re: Trying To Shutdown WPF App - Application.Current is null

2-Nov-11 7:49

Probably calling this method too early??

Kevin Marois2-Nov-11 8:38

Re: Trying To Shutdown WPF App - Application.Current is null

2-Nov-11 8:38

But during runtime you would thnk that Application.Current would exist.

Everything makes sense in someone's mind

SledgeHammer012-Nov-11 8:47

Re: Trying To Shutdown WPF App - Application.Current is null

2-Nov-11 8:47

As I said, depends from where. If you are calling your method really early on (say in the app constructor, or a main() override, the start up code that inits that property hasn't executed yet.

Pete O'Hanlon2-Nov-11 8:52

Pete O'Hanlon

2-Nov-11 8:52

I assume that you are running this prior to the initialisation of the application pump. If you take control of starting your application (i.e. you don't just rely on StartupUri), you need to be aware of when your application actually "starts". I'd say that your logic would be better expressed as:

if (login())
{
  // Startup the app and show the main window.
}
// If you get here without the "pump" taking over then you just fall out of your app gracefully.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Is there an existing Color-picker in WPF/Silverlight ?

Loveisasea2-Nov-11 5:22

Loveisasea

2-Nov-11 5:22

as captioned.

Is there an existing control to pick a color just like the datepicker ? I can not find it in the MSDN library ....

Re: Is there an existing Color-picker in WPF/Silverlight ?

Mark Salsbery2-Nov-11 5:25

Mark Salsbery

2-Nov-11 5:25

No but there's lots of example source code floating around...

Mark Salsbery
Java | [Coffee]

Re: Is there an existing Color-picker in WPF/Silverlight ?

Pete O'Hanlon2-Nov-11 5:28

Pete O'Hanlon

2-Nov-11 5:28

Our very own Sacha Barber has implemented just such a thing[^]. Enjoy.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

Re: Is there an existing Color-picker in WPF/Silverlight ?

Abhinav S2-Nov-11 18:13

Items collection must be empty before using ItemsSource.

2-Nov-11 18:13

VectorLight has a color picker[^] that you could use.

jhoga2-Nov-11 4:39

jhoga

2-Nov-11 4:39

I keep getting this error. I kind of new to wpf and not sure what the issue is.
Here is my code:

XML

<DataGrid AutoGenerateColumns="False" Height="770" Name="DataGrid1" Width="1506" ItemsSource="{Binding}">
        <Style TargetType="{x:Type DataGridRow}" >
            <Style.Triggers>
                <DataTrigger Binding="{Binding Alert_Level}" Value="1">
                    <Setter Property="Background" Value="LightYellow" />
                </DataTrigger>
            </Style.Triggers>
        </Style>

<DataGrid.Columns>

XML

<DataGridTextColumn Header="ID" Binding="{Binding TicketID}" IsReadOnly="True" Width="70" FontSize="24" />
            <DataGridTextColumn Header="Date" Binding="{Binding Date_Entered}" IsReadOnly="True" Width="100" FontSize="24" />
            <DataGridTextColumn Header="Input By" Binding="{Binding Requestor}" IsReadOnly="True" Width="200" FontSize="24"/>
            <DataGridTextColumn Header="Telephone" Binding="{Binding Requestor_telep}" IsReadOnly="True" Width="120" FontSize="24"/>
            <DataGridTextColumn Header="Status" Binding="{Binding Status}" IsReadOnly="True" Width="120" FontSize="24"/>
            <DataGridTextColumn Header="Alert" Binding="{Binding Alert_Level}" IsReadOnly="True" Width="40" FontSize="24"/>
            <DataGridTextColumn Header="Assigned" Binding="{Binding Assigned_To}" IsReadOnly="True" Width="200" FontSize="24"/>
            <DataGridTextColumn Header="Issue" Binding="{Binding Problem_detail}" IsReadOnly="True" Width="300*" FontSize="24"/>
        </DataGrid.Columns>

</DataGrid>

Thanks

Re: Items collection must be empty before using ItemsSource.

Mark Salsbery2-Nov-11 5:23

Mark Salsbery

2-Nov-11 5:23

I would guess based on what you've shown, the Style ends up being just a datagrid item (an object representing a datagrid row). That style should be in the resources somewhere, for example

<DataGrid ...>
    <DataGrid.Resources>
        <Style TargetType="{x:Type DataGridRow}" >
            <Style.Triggers>
                <DataTrigger Binding="{Binding Alert_Level}" Value="1">
                    <Setter Property="Background" Value="LightYellow" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGrid.Resources>
    <DataGrid.Columns>
     ...
    </DataGrid.Columns>
<DataGrid>

Mark Salsbery
Java | [Coffee]

Re: Items collection must be empty before using ItemsSource.

jhoga2-Nov-11 5:52

jhoga

2-Nov-11 5:52

Thanks mark,
That took care of my error. I still can not get the background to show a color base on a value. But that is a complete separate issue. Thanks for your help Wink | ;)

Re: Items collection must be empty before using ItemsSource.

Mark Salsbery2-Nov-11 7:06

Mark Salsbery

2-Nov-11 7:06

jhoga wrote:
I still can not get the background to show a color base on a value.

Maybe the resource needs to be at least one level up the tree from the datagrid.

Regardless, perhaps try using ItemContainerStyle instead, something like this

HTML

<DataGrid ...>
    <DataGrid.ItemContainerStyle>
        <Style TargetType="{x:Type DataGridRow}" BasedOn="{StaticResource {x:Type DataGridRow}}" >
            <Style.Triggers>
                <DataTrigger Binding="{Binding Alert_Level}" Value="1">
                    <Setter Property="Background" Value="LightYellow" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGrid.ItemContainerStyle>
    <DataGrid.Columns>
     ...
    </DataGrid.Columns>
<DataGrid>

Mark Salsbery
Java | [Coffee]

Re: Items collection must be empty before using ItemsSource.

jhoga2-Nov-11 8:57

jhoga

2-Nov-11 8:57

Thanks Mark,
I tried that with no luck. I found the issue the value of Alert_Level was not numeric. Once I changed it to an int everything worked fine. Thanks for your help. Smile | :)

How to make listbox list items in horizontal

Loveisasea1-Nov-11 19:47

Loveisasea

1-Nov-11 19:47

By default listbox list items in vertical. Now I want to list them in horizontal. I remember this can only be set in ListBox's Style. But I forget the full name of the Property and can not find it out in the past 2 hours. Cry | :((

Anyone know this property name?

Re: How to make listbox list items in horizontal

Abhinav S1-Nov-11 19:56