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Combobox Performance with many Elements

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ComboBox

This is a migrated thread and some comments may be shown as answers.

15 Answers, 1 is accepted

answered on 11 Nov 2009, 10:51 AM

Valeri,
thanks for answering. It does not "feel" that much different.
Is there anything else I need to do ?
Code currently looks like this:

    
                        <telerik:RadComboBox Margin="6" 
        
                                             Name="cbSelection" 
        
                                             ItemsSource="{Binding Path=ItemsSource, Mode=OneWay}" 
        
                                             SelectedItem="{Binding Path=SelectedItem, Mode=TwoWay}"> 
        
                            <telerik:RadComboBox.ItemsPanel> 
        
                                <ItemsPanelTemplate> 
        
                                    <VirtualizingStackPanel /> 
        
                                </ItemsPanelTemplate> 
        
                            </telerik:RadComboBox.ItemsPanel> 
        
                            <telerik:RadComboBox.ItemTemplate> 
        
                                <DataTemplate> 
        
                                    <StackPanel Orientation="Horizontal"> 
        
                                        <TextBlock Margin="1,1,1,2" 
        
                                                   Text="{Binding Path=Bezeichnung, Mode=OneWay}" /> 
        
                                        <TextBlock Margin="2,1,1,2" 
        
                                                   Name="tbSeparator1" 
        
                                                   Text="-" /> 
        
                                        <TextBlock Margin="2,1,1,0" 
        
                                                   Text="{Binding Path=Straße, Mode=OneWay}" /> 
        
                                    </StackPanel> 
        
                                    <DataTemplate.Triggers> 
        
                                        <DataTrigger Binding="{Binding Path=Straße}" 

                                                     Value="{x:Null}"> 
        
                                            <Setter TargetName="tbSeparator1" 
        
                                                    Property="Text" 
        
                                                    Value="" /> 
        
                                        </DataTrigger> 
        
                                        <DataTrigger Binding="{Binding Path=Straße}" 
        
                                                     Value=""> 
        
                                            <Setter TargetName="tbSeparator1" 
        
                                                    Property="Text" 
        
                                                    Value="" /> 
        
                                        </DataTrigger> 
        
                                    </DataTemplate.Triggers> 
        
                                </DataTemplate> 
        
                            </telerik:RadComboBox.ItemTemplate> 
        
                        </telerik:RadComboBox>

Also, I'm using wpf while you'd blogged on Silverlight, Don't know if is make a difference in this case..

answered on 04 Dec 2009, 07:30 PM

Thanks. In the meantime I got around this by creating a DataView that prunes elements and makes users start entering text to get elements in to the combobox:

    
            private void someComboBox_KeyUp(object sender, KeyEventArgs e) 
        
                    { 
        
                        // Check type. 
        
                        if (sender.GetType() == typeof(RadComboBox)) 
        
                        { 
        
                            // Cast combobox. 
        
                            RadComboBox myComboBox = (RadComboBox)sender; 
        
                            // Check length (depending on how many rows you have you might want to change this). 
        
                            if (myComboBox.Text.Length > 1) 
        
                            { 
        
                                // Get a DataView with items that start with string entered... this is assuming you have your data in a DataTable called myDataTable sitting in memory. 
        
                                myDataTable.DefaultView.RowFilter = string.Format("MyColumn LIKE '{0}*'", myComboBox.Text); 
        
                                myComboBox.DataContext = myDataTable.DefaultView.ToTable(); 
        
                            } 
        
                        } 
        
                    }

Pretty simple implementation and you could easily customize it for your own uses. This might not be good for all users hitting this performance issue, but for times where it's acceptable to do this it should work.

Cheers,

-Dean

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Combobox Performance with many Elements

15 Answers, 1 is accepted