[英]How to add different ListBox items WPF
我開始創建一個ListBox並設置一個ListBox.ItemTemplate,但我無法弄清楚我如何控制ListBox添加一個項目的布局作為收到的消息或發送(就像Whatsapp)。
這是我的代碼:
<ListBox Name="ChatListBox" ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.HorizontalScrollBarVisibility="Disabled" Background="#00FFFFFF" BorderBrush="{x:Null}" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Background="#00FFFFFF"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="Focusable" Value="False"/>
</Style>
</ListBox.ItemContainerStyle>
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<!--If the user sends a msg-->
<Grid.ColumnDefinitions>
<ColumnDefinition Width="9*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Grid.Column="0" Margin="0" BorderThickness="1" BorderBrush="#9f9f9f" Background="#c4df9b" CornerRadius="10">
<TextBlock Name="MsgText" Background="#c4df9b" Foreground="Black" TextAlignment="Center" TextWrapping="Wrap" Margin="5" Text="{Binding text}" FontSize="14"/>
</Border>
<Image Grid.Column="1" Source="Images/user.png" Margin="5" Height="{Binding ElementName=MsgText, Path=ActualHeight}"/>
<!--
If the user receives a msg
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="9*"/>
</Grid.ColumnDefinitions>
<Image Grid.Column="0" Source="Images/user.png" Margin="5" Height="{Binding ElementName=MsgText, Path=ActualHeight}"/>
<Border Grid.Column="1" Margin="0" BorderThickness="1" BorderBrush="#9f9f9f" Background="#c4df9b" CornerRadius="10">
<TextBlock Name="MsgText" Background="#c4df9b" Foreground="Black" TextAlignment="Center" TextWrapping="Wrap" Margin="5" Text="{Binding text}" FontSize="14"/>
</Border>-->
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
這是我的c#代碼:
List<ChatItem> chatItem = new List<ChatItem>();
chatItem.Add(new ChatItem() { text = "Hello...", isFromUser = false });
chatItem.Add(new ChatItem() { text = "hi!", isFromUser = true });
chatItem.Add(new ChatItem() { text = "this is a test, this is a test, this is a test, this is a test, this is a test, this is a test, this is a test, this is a test, this is a test, this is a test", isFromUser = false });
ChatListBox.ItemsSource = chatItem;
這就是ListBox的處理方式:
有沒有辦法在帶有WPF的ListBox中添加IF語句? 或者我如何控制要添加的ListBox.ItemTemplate。
如果您的消息屬於同一類,則可以使用itemsTemplateSelector,如http://codingbandit.com/blog/?p=8
如果有不同的類,你應該使用datatemplate數據類型屬性,如在條件列表itemtemplate或datatemplate在WPF中
也許這會給你一個想法
XAML
<Window x:Class="Q1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Q1"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<DataTemplate x:Key="intDataTemplate">
<TextBox Text="{Binding Path=.}" Width="80"/>
</DataTemplate>
<DataTemplate x:Key="stringDataTemplate">
<TextBlock Text="{Binding Path=.}"/>
</DataTemplate>
<local:MyDataTemplateSelector IntDataTemplate="{StaticResource intDataTemplate}"
StringDataTemplate="{StaticResource stringDataTemplate}"
x:Key="myDataTemplateSelector"/>
</Window.Resources>
<Grid>
<ListBox x:Name="myListBox" ItemsSource="{Binding}"
ItemTemplateSelector="{StaticResource myDataTemplateSelector}">
</ListBox>
</Grid>
代碼隱藏
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace Q1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
List<System.Object> myList = new List<object>();
myList.Add(1);
myList.Add("Alpha");
myList.Add(2);
myList.Add("Beta");
myList.Add(3);
myList.Add("Gamma");
myListBox.DataContext = myList;
}
}
}
DataTemplateSelector
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Q1
{
public class MyDataTemplateSelector : System.Windows.Controls.DataTemplateSelector
{
public System.Windows.DataTemplate IntDataTemplate { get; set; }
public System.Windows.DataTemplate StringDataTemplate { get; set; }
public MyDataTemplateSelector()
{
IntDataTemplate = new System.Windows.DataTemplate();
StringDataTemplate = new System.Windows.DataTemplate();
}
public override System.Windows.DataTemplate SelectTemplate(object item, System.Windows.DependencyObject container)
{
if (item is Int32)
{
return IntDataTemplate;
}
else
{
return StringDataTemplate;
}
}
}
}
另一種選擇是簡單地使用數據觸發器:
<DataTemplate x:Key="ToTemplate">
... etc ...
</DataTemplate>
<DataTemplate x:Key="FromTemplate">
... etc ...
</DataTemplate>
<Style TargetType="ListBoxItem">
<Style.Triggers>
<DataTrigger Binding="{Binding isFromUser}" Value="false">
<Setter Property="Template" Value="{StaticResource ToTemplate}" />
</DataTrigger>
<DataTrigger Binding="{Binding isFromUser}" Value="true">
<Setter Property="Template" Value="{StaticResource FromTemplate}" />
</DataTrigger>
</Style.Triggers>
</Style>
您可以使用DataTemplateSelector根據您的數據選擇模板,這是一個示例。
對於此示例,我將使用消息,客戶端消息和服務器消息:
public abstract class Message
{
public string Content { get; set; }
public override string ToString()
{
return Content;
}
}
public class ServerMessage : Message
{
}
public class ClientMessage : Message
{
}
通過這種方式,我可以檢查對象的類型並應用某些模板。
讓我們定義我們的模板和選擇器:
XAML:
<DataTemplate x:Key="clientTemplate" >
<TextBlock Text="{Binding Content}"
Foreground="Red"/>
</DataTemplate>
<DataTemplate x:Key="serverClient">
<TextBlock Text="{Binding Content}"
Foreground="Green"/>
</DataTemplate>
<local:MessageTemplateSelector x:Key="messageSelector"
ServerTemplate="{StaticResource serverClient}"
ClientTemplate="{StaticResource clientTemplate}"/>
DataTemplateSelector
public class MessageTemplateSelector : DataTemplateSelector
{
public DataTemplate ClientTemplate { get; set; }
public DataTemplate ServerTemplate { get; set; }
public override System.Windows.DataTemplate SelectTemplate(object item, System.Windows.DependencyObject container)
{
if (item.GetType() == typeof(ClientMessage))
return ClientTemplate;
return ServerTemplate;
}
}
首先,正如您所看到的,我在Selector上創建了兩個DataTemplate屬性,我通過XAML設置它,這樣做很容易檢索DataTemplate,最后我只是比較參數接收的項目,即綁定對象(消息),並檢查其類型並返回模板。
就是這樣,它就像預期的那樣工作。
更新:假設您希望模板根據其類型進行項目,就像我的示例一樣,您可以在不使用TemplateSelector的情況下使用相同的內容,您可以定義模板的DataType:
<Window.Resources>
<DataTemplate DataType="{x:Type local:ClientMessage}">
<TextBlock Text="{Binding Content}"
Foreground="Red"/>
</DataTemplate>
<DataTemplate DataType="{x:Type local:ServerMessage}">
<TextBlock Text="{Binding Content}"
Foreground="Green"/>
</DataTemplate>
</Window.Resources>
這樣,將根據對象的類型自動選擇模板。
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