zoukankan      html  css  js  c++  java

  • 【WPF异常】在使用 ItemsSource 之前，项集合必须为空

     1 <DataGrid x:Name="dataGrid" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Width="620" Height="269" AutoGenerateColumns="False" GridLinesVisibility="None" CanUserDeleteRows="False"
 2                     CanUserAddRows="False" ItemsSource="{Binding ListStudent}"> 
 3             <DataGridTextColumn Header="编号" Width="80" Binding="{Binding Student.studentid}"/>
 4             <DataGridTextColumn Header="姓名" Width="80" Binding="{Binding Student.name}"/>
 5             <DataGridTextColumn Header="年龄" Width="80" Binding="{Binding Student.age}"/>
 6             <DataGridTextColumn Header="性别" Width="80" Binding="{Binding Student.sex}"/>
 7             <DataGridTextColumn Header="特点" Width="120" Binding="{Binding Student.remark}"/>
 8             <DataGridTemplateColumn Header="选中" SortMemberPath="IsSelected" Width="120">
 9                 <DataGridTemplateColumn.CellTemplate>
10                     <DataTemplate>
11                         <CheckBox IsChecked="{Binding Path=IsSelected,UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" HorizontalAlignment="Center" Command="{Binding Path=DataContext.SelectStudentItemCommand,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type DataGrid}}}"
12                     />
13                     </DataTemplate>
14                 </DataGridTemplateColumn.CellTemplate>
15             </DataGridTemplateColumn> 
16         </DataGrid>

    报错“在使用 ItemsSource 之前，项集合必须为空”

    观察一下便可发现设计器里没有正确显示各列，是因为少了DataGrid.Columns节点

     1 <DataGrid x:Name="dataGrid" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Width="620" Height="269" AutoGenerateColumns="False" GridLinesVisibility="None" CanUserDeleteRows="False"
 2                     CanUserAddRows="False" ItemsSource="{Binding ListStudent}">
 3             <DataGrid.Columns>
 4             <DataGridTextColumn Header="编号" Width="80" Binding="{Binding Student.studentid}"/>
 5             <DataGridTextColumn Header="姓名" Width="80" Binding="{Binding Student.name}"/>
 6             <DataGridTextColumn Header="年龄" Width="80" Binding="{Binding Student.age}"/>
 7             <DataGridTextColumn Header="性别" Width="80" Binding="{Binding Student.sex}"/>
 8             <DataGridTextColumn Header="特点" Width="120" Binding="{Binding Student.remark}"/>
 9             <DataGridTemplateColumn Header="选中" SortMemberPath="IsSelected" Width="120">
10                 <DataGridTemplateColumn.CellTemplate>
11                     <DataTemplate>
12                         <CheckBox IsChecked="{Binding Path=IsSelected,UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" HorizontalAlignment="Center" Command="{Binding Path=DataContext.SelectStudentItemCommand,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type DataGrid}}}"
13                     />
14                     </DataTemplate>
15                 </DataGridTemplateColumn.CellTemplate>
16             </DataGridTemplateColumn>
17             </DataGrid.Columns>
18         </DataGrid>

    改为以上即可
  • 相关阅读:
    计算机网络杂烩
    网络体系、网络模型其他
    数据通信（系统）的物理要素
    数据通信历史
    没有备案的网站域名能解析吗
    dedecms列表页有图调用缩略图无图留空的方法
    dede 你所上传的软件类型不在许可列表，请更改系统对扩展名限定的配置
    跟版网 > 织梦教程 > 织梦安装使用 > 织梦DedeCMS附件上传大
    从#65279字符看dede模板页面编码问题
    sublime text如何保存为uft-8无bom编码格式文件
  • 原文地址：https://www.cnblogs.com/dyfisgod/p/7064801.html
Copyright © 2011-2022 走看看