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ListView:ListViewGridLayout causing "Specified cast is not valid"

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Brian
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Brian asked on 22 Jan 2019, 05:31 PM

Hi, I'm sure this is something I'm just missing but I need another pair of eyes...  I have a Content Page that I put the below listview in it and I wanted the list to have a span count of 2, like your example online.   I was have trouble with the layout and I removed the LayoutDefinition and once it started working properly (single list view) I add the Definition back in (copy/paste) and compiled and got the error.

If I remove the LayoutDefinition tag it works....

My includes:

xmlns:tDataCtrl="clr-namespace:Telerik.XamarinForms.DataControls;assembly=Telerik.XamarinForms.DataControls"
xmlns:tListView="clr-namespace:Telerik.XamarinForms.DataControls.ListView;assembly=Telerik.XamarinForms.DataControls"
            

 

 

<tDataCtrl:RadListView x:Name="memberList" ItemsSource="{Binding TeamMembers}"  Margin="20,0,0,0"   BackgroundColor="White"   VerticalOptions="FillAndExpand" IsVisible="{Binding MembersVisible}">
            
                              <tDataCtrl:RadListView.ItemTemplate>
                                <DataTemplate>
                                  <tListView:ListViewTemplateCell>
                                    <tListView:ListViewTemplateCell.View>
                                         <Grid BackgroundColor="White">
                                            <Grid.RowDefinitions>
                                              <RowDefinition Height="220"/>
                                              <RowDefinition Height="18"/>
                                              <RowDefinition Height="18"/>
                                            </Grid.RowDefinitions>
                                            <Grid.ColumnDefinitions>
                                              <ColumnDefinition Width="Auto"/>
                                            </Grid.ColumnDefinitions>
                                            <ff:CachedImage Source="{Binding Image}"  HeightRequest="220"    Aspect="AspectFit"    Grid.Row="0"   
                                                      HorizontalOptions="CenterAndExpand"   VerticalOptions="CenterAndExpand"  Margin="0,0,10,0"/>
                                            <Label Text="{Binding FullName}"   FontSize="{Binding RoleToPresent}"   LineBreakMode="WordWrap"    TextColor="Black"  Margin="8,0,8,0" Grid.Row="1" HorizontalOptions="Start"/>
                                            <Label Text="{Binding RoleToPresent}" FontSize="{Binding RoleToPresent}" LineBreakMode="WordWrap"   TextColor="Black" Margin="8,0,8,0"  Grid.Row="2" HorizontalOptions="Start"/>
                                         </Grid>       
                                        </tListView:ListViewTemplateCell.View>
                                      </tListView:ListViewTemplateCell>
                                    </DataTemplate>
                                  </tDataCtrl:RadListView.ItemTemplate>
                                   <tDataCtrl:RadListView.LayoutDefinition >
                             
                                        <tListView:ListViewGridLayout Orientation="Vertical"  ItemLength="280"  SpanCount="2"    VerticalItemSpacing="30"  HorizontalItemSpacing="30"/>
                                   </tDataCtrl:RadListView.LayoutDefinition>
                        </tDataCtrl:RadListView> 

 

 

Thank you,

Brian

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Brian
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answered on 22 Jan 2019, 05:39 PM

Ok, I fixed by putting the LayoutDefinition about the ItemTemplate, which worries me. What do I have declared in the ItemTemplate thattells the compiler to expect a different class in the LayoutDefinition??  uhg! 

I still need another set of eyes to review and tell me where I'm going wrong here please.

Thanks,

Brian

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Didi
Telerik team
answered on 24 Jan 2019, 07:26 AM
Hi Brian,

Thank you for the provided code.

I have created a sample based on the attached code but I the RadListView GridLayout definition works as expected. Please take a look at the attached project. Could you please give us more information about:

- which versions of Telerik UI for Xamarin and Xamarin.Forms are used in the project
- on which platform the issue can be reproduced.

Also could you please verify that the issue can be reproduced in the attached project. If not, may I ask you to modify it according your setup and send it back to me? In this way I could research it further. Please note that you should open a support ticket and attach the project there because in the forum only image attachments are allowed.

Looking forward to your reply.

Regards,
Didi
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Brian
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answered on 24 Jan 2019, 03:41 PM

HI Didi, I went back to the view where this occurred and I am compiling without error even if the LayoutDefinition is below the template so I'm not sure why it error earlier.   I also loaded your project and it too is compiling.   It must have been something temporary.  I'd say this is not an issue.

Thank you!

B

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Didi
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