BindingExpression路径错误：'lim'上找不到'username'属性（请帮助） [英] BindingExpression path error: 'username' property not found on 'lim'(pls help)

问题描述

我尝试使用此代码绑定后收到此错误

（任何人都可以帮我解决此错误吗？）

 <  网格    x：名称  =  ContentGrid   保证金  =  0 ，22,0，-22    Grid.Row   =  1 >  
 <   ListBox    高度  =  444    Horizo​​ntalAlignment   = 左   保证金  =   20,81,0,0   名称  =  listBox1    VerticalAlignment   =  Top   宽度  =  434   >  
 <   ListBox.ItemTemplate  >  
 <   DataTemplate  >  
 <   StackPanel    方向  = 水平 >  
 <   TextBlock    文本  =   {Binding username}    /  >  
 <   TextB锁   文字  =  {Binding password}    /  >  
 <   TextBlock  < span class =code-attribute>  文本  =  {Binding gender}    /  >  
 <   / StackPanel  >  
 <   / DataTemplate  >  
 <   / ListBox.ItemTemplate  >  
 <   / ListBox  >  
 <   / Grid  >  

错误

System.Windows.Data错误：BindingExpression路径错误：''用户名在''lim''''System.String''找不到属性（HashCode = 339799040）。 BindingExpression：Path =''username''DataItem =''lim''（HashCode = 339799040）; target元素是''System.Windows.Controls.TextBlock''（Name =''''）; target属性是''Text''（类型''System.String''）..









我的整个项目代码

xaml代码

  <   phone：PhoneApplicationPage   
   
           x：Class   =  Epromo.MainPage  
   
           xmlns   =  http://schemas.microsoft.com/winfx/2006/xaml/presentation  
   
           xmlns：x   =  http://schemas.microsoft.com/winfx/2006/xaml  
   
           xmlns：phone   =  clr-namespace：Microsoft.Phone.Controls; assembly = Microsoft.Phone  
   
           xmlns：shell   =  clr-namespace：Microsoft.Phone.Shell; assembly = Microsoft.Phone  
   
           xmlns：d   =  http://schemas.microsoft.com/expression/ blend / 2008  
   
           xmlns：mc   =  http://schemas.openxmlformats.org/markup-compatibility/2006  
   
           mc：可忽略  =  d    d：DesignWidth   =  480    d：DesignHeight   =  768  
   
           FontFamily   =  {StaticResource PhoneFontFamilyNormal}  
   
           FontSize   =  {StaticResource PhoneFontSizeNormal}  
   
          前景  =  {StaticResource PhoneForegroundBrush}  
   
           SupportedOrientations   = 肖像   方向  =  Portrait  
   
           shell：SystemTray.IsVisible   =  True    >  
 
 <！ -     Layo utRoot是放置所有页面内容的根网格   - >   
 <  网格    x：名称  =  LayoutRoot   < span class =code-attribute>背景  = 透明 >  
 <   Grid.RowDefinitions  < span class =code-keyword>>  
 <   RowDefinition    高度  =  83  /  >  
 <   RowDefinition    高度  =  685 *  /  >  
 <   / Grid.RowDefinitions  > ;  
 
 <！ -     TitlePanel包含应用程序名称和页面标题   - >   
 <   StackPanel     x：名称  =  TitlePanel   保证金  =   9,17,3,0 >  <   / StackPanel  >  
 <  按钮   内容  = 正在进行      Horizo​​ntalAlignment   = 左   保证金  =   -  5,85,0,0    VerticalAlignment   =  Top    Grid.RowSpan   =  2   宽度  =  195  /   >  
 <  按钮   内容  = 大多数视图    Horizo​​ntalAlignment   = 左   保证金  =  161,85,0,0    VerticalAlignment   =  Top    Grid.RowSpan   =   2   宽度 < span class =code-keyword> =  186    RenderTransformOrigin   =  0.5,0.5  /  >  
 <  按钮   内容  = 即将推出    Horizo​​ntalAlignment   = 左   保证金  =  321， 85，-13,0    VerticalAlignment   =  Top    Grid.RowSpan   =  2   < span class =code-attribute>宽度  =  170    FontSize   =  20   高度  =  72  /  >  
 <  网格    x：名称  =  ContentGrid    保证金  =  0,22,0，-22    Grid.Row   =  1 >  
 <   ListBox    高度  =  444    Horizo​​ntalAlignment   = 左   保证金  =  20,81,0,0   名称  =  listBox1    VerticalAlignment   =  Top   宽度  =  434   >  
 <   ListBox.ItemTemplate  >  
 <   DataTemplate  >  
 <   StackPanel    方向  = 水平 >  
 <   TextBlock  < span class =code-attribute>  文本  =  {Binding username}    /  >  
 <   TextBlock    文字  =  {绑定密码}    /  >  
 <   TextBlock    文字  =  {绑定性别}    /  >  
 <   / StackPanel  >  
 <   / DataTemplate  >  
 <   / ListBox.ItemTemplate  >  
 <   / ListBox  >  
 <   / Grid   >  
 <  按钮   内容  = 注册    FontSize   =  17   高度  =  60    名称  = < span class =code-keyword>注册   宽度  =  120   点击  =  signup_Click   保证金  =  371,43，-11,647    Grid.RowSpan   =  2    /  >  
 <   TextBlock     x：名称  =  ApplicationTitle   样式  =  {StaticResource PhoneTextNormalStyle}    FontSize   =  24    FontFamily   =  Times New Roman < span class =code-attribute>  高度  =  34   保证金  =  4,0,32,49 >  
 
 <  运行   文字  =  Epromo    /  >  <   / TextBlock  >  
 <！ -     ContentPanel  - 在此处添加其他内容   - >   
 < ;   / Grid  >  
 
 <   / phone：PhoneApplicationPage  >  

cs code



< pre lang =cs> 使用 Epromo.ServiceReference1;

命名空间 Epromo
{
public partial class MainPage：PhoneApplicationPage
{
private Service1Client _serviceClient;
// 构造函数
public MainPage（）
{
InitializeComponent（）;
已加载+ = 新 RoutedEventHandler（Post_Loaded）;
}
void Post_Loaded（ object sender，EventArgs e）
{
_serviceClient = new Service1Client（）;
_serviceClient.ListPostCompleted + = new EventHandler< ListPostCompletedEventArgs>（getList_Completed）;
_serviceClient.ListPostAsync（）;

}
void getList_Completed（ object sender，ListPostCompletedEventArgs e）
{
listBox1.ItemsSource = e.Result;
}

private void signup_Click（ object sender，RoutedEventArgs e）
{
NavigationService.Navigate（ new Uri（ / signupPage.xaml，UriKind.Relative））;
}





}
}

解决方案

修改绑定

< TextBlock Text =" {Binding username}" />

to

< TextBlock Text =" {Binding}" />



并删除其他两个...检查结果！你得到了什么？



提示：你正在将DataTable转换为List，其中每个记录的列组成一个完整的新记录。在你的清单中，例如：

DataTable看起来像：



User1 |密码1 |男性

User2 |密码2 |男性

User3 |密码3 |女性



看起来像：

用户1

密码1

男

用户2

密码2

男

用户3

密码3

女性





ItemsControl现在尝试显示表示为字符串的所有9条记录。对于每个字符串，它应用DataTemplate。绑定到例如username现在尝试在Type String的离子上获取名为username的属性。



另一条线索：修改Binding，使其显示为：

< TextBlock Text =" {Binding Length}" />

（绑定到属性字符串中实际应存在的属性长度）



考虑到这一点，请重新检查绑定错误。所有这些信息都在那里！



我希望我能稍微清理一下

i am getting this error after i try to binding using this code
(can anyone help me with this error?)

<Grid x:Name="ContentGrid" Margin="0,22,0,-22" Grid.Row="1">
           <ListBox Height="444" HorizontalAlignment="Left" Margin="20,81,0,0" Name="listBox1" VerticalAlignment="Top" Width="434" >
               <ListBox.ItemTemplate>
                   <DataTemplate>
                       <StackPanel Orientation="Horizontal">
                           <TextBlock Text="{Binding username}" />
                           <TextBlock Text="{Binding password}" />
                           <TextBlock Text="{Binding gender}" />
                       </StackPanel>
                   </DataTemplate>
               </ListBox.ItemTemplate>
           </ListBox>
       </Grid>

error
System.Windows.Data Error: BindingExpression path error: ''username'' property not found on ''lim'' ''System.String'' (HashCode=339799040). BindingExpression: Path=''username'' DataItem=''lim'' (HashCode=339799040); target element is ''System.Windows.Controls.TextBlock'' (Name=''''); target property is ''Text'' (type ''System.String'')..




my whole project code
xaml code

<phone:PhoneApplicationPage

    x:Class="Epromo.MainPage"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"

    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"

    FontFamily="{StaticResource PhoneFontFamilyNormal}"

    FontSize="{StaticResource PhoneFontSizeNormal}"

    Foreground="{StaticResource PhoneForegroundBrush}"

    SupportedOrientations="Portrait" Orientation="Portrait"

    shell:SystemTray.IsVisible="True" >

    <!--LayoutRoot is the root grid where all page content is placed-->
    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Grid.RowDefinitions>
            <RowDefinition Height="83"/>
            <RowDefinition Height="685*"/>
        </Grid.RowDefinitions>

        <!--TitlePanel contains the name of the application and page title-->
        <StackPanel x:Name="TitlePanel" Margin="9,17,3,0"></StackPanel>
        <Button Content="On going"  HorizontalAlignment="Left" Margin="-5,85,0,0" VerticalAlignment="Top" Grid.RowSpan="2" Width="195"/>
        <Button Content="most view" HorizontalAlignment="Left" Margin="161,85,0,0" VerticalAlignment="Top" Grid.RowSpan="2" Width="186" RenderTransformOrigin="0.5,0.5"/>
        <Button Content="Coming soon" HorizontalAlignment="Left" Margin="321,85,-13,0" VerticalAlignment="Top" Grid.RowSpan="2" Width="170" FontSize="20" Height="72"/>
        <Grid x:Name="ContentGrid" Margin="0,22,0,-22" Grid.Row="1">
            <ListBox Height="444" HorizontalAlignment="Left" Margin="20,81,0,0" Name="listBox1" VerticalAlignment="Top" Width="434" >
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <TextBlock Text="{Binding username}" />
                            <TextBlock Text="{Binding password}" />
                            <TextBlock Text="{Binding gender}" />
                        </StackPanel>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </Grid>
        <Button Content="sign up" FontSize="17" Height="60" Name="signup" Width="120" Click="signup_Click" Margin="371,43,-11,647" Grid.RowSpan="2" />
        <TextBlock x:Name="ApplicationTitle" Style="{StaticResource PhoneTextNormalStyle}" FontSize="24" FontFamily="Times New Roman" Height="34" Margin="4,0,32,49">

                <Run Text="Epromo" /></TextBlock>
        <!--ContentPanel - place additional content here-->
    </Grid>

</phone:PhoneApplicationPage>

cs code

using Epromo.ServiceReference1;

namespace Epromo
{
    public partial class MainPage : PhoneApplicationPage
    {
        private Service1Client _serviceClient;
        // Constructor
        public MainPage()
        {
            InitializeComponent();
            Loaded += new RoutedEventHandler(Post_Loaded);
        }
        void Post_Loaded(object sender, EventArgs e)
        {
            _serviceClient = new Service1Client();
            _serviceClient.ListPostCompleted += new EventHandler<ListPostCompletedEventArgs>(getList_Completed);
            _serviceClient.ListPostAsync();

        }
        void getList_Completed(object sender, ListPostCompletedEventArgs e)
        {
            listBox1.ItemsSource = e.Result;
        }

        private void signup_Click(object sender, RoutedEventArgs e)
        {
            NavigationService.Navigate(new Uri("/signupPage.xaml", UriKind.Relative));
        }





    }
}

解决方案

modify the Binding
<TextBlock Text="{Binding username}" />
to
<TextBlock Text="{Binding}" />

and remove the other two...examine the result! what are you getting?

Hint: your are transforming the DataTable to a List, where the columns of each record makes up a complete new "record" in your list, e.g.:
The DataTable looks like:

User1 | Password1 | male
User2 | Password2 | male
User3 | Password3 | female

THe lsit looks like:
User1
Password1
male
User2
Password2
male
User3
Password3
female


The ItemsControl now tries to display all of those 9 records represented as a string. for each string it applies the DataTemplate. The Binding to e.g. "username" now tries to get a property named "username" on an ionstance of Type String.

Another clue: Modify the Binding, so that it reads:
<TextBlock Text="{Binding Length}" />
(Binding to a Property "Length" that should actually exist on type String)

With this in mind, reexamine the Binding-Error. All this Information is in there!

I hope i could clear up things a little bit

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