wpf DataGrid - “双向绑定需要 Path 或 XPath。”
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DataGrid - "Two-way binding requires Path or XPath."
提问by Lau
I would like to display on DataGrid my object database
我想在 DataGrid 上显示我的对象数据库
public class Student
{
public string Imie { get; set; }
public string Nazwisko { get; set; }
string Numer { get; set; }
internal List<Telefon> Telefony { get; set; }
internal Adres Adres { get; set; }
}
In Adresand Telefonclass I have obviously some extra fields.
在Adres和Telefon课程中，我显然有一些额外的字段。
My XAML:
我的 XAML：
<DataGrid Name="dataGrid" ItemsSource="{Binding Student}" AutoGenerateColumns="False" CellEditEnding="dataGrid_CellEditEnding" CurrentCellChanged="dataGrid_CurrentCellChanged" PreviewKeyDown="dataGrid_PreviewKeyDown">
<DataGrid.Columns>
<DataGridTextColumn Header="Imie" Binding="{Binding Imie}"/>
<DataGridTextColumn Header="Nazwisko" Binding="{Binding Nazwisko}"/>
<DataGridTextColumn Header="Numer" Binding="{Binding Numer}"/>
<DataGridTextColumn Header="Ulica" Binding="{Binding Adres.Ulica}"/>
<DataGridTextColumn Header="KodPocztowy" Binding="{Binding Adres.KodPocztowy}"/>
<DataGridTextColumn Header="Miasto" Binding="{Binding Adres.Miasto}"/>
<DataGridTextColumn Header="Tel. Numer" Binding="{Binding Telefon.Numer}"/>
<DataGridTextColumn Header="Tel. Operator" Binding="{Binding Telefon.Operator}"/>
</DataGrid.Columns>
</DataGrid>
I can easily get and set Imie, Nazwiskoand Numerfields but when i'm trying to set value of Ulica(field in Adresclass) compiler gives me this exception:
我可以轻松获取和设置Imie、Nazwisko和Numer字段，但是当我尝试设置Ulica 的值（Adres类中的字段）时，编译器给了我这个异常：
InvalidOperationException was unhandled
Two-way binding requires Path or XPath.
Thanks for help.
感谢帮助。
回答by Rohit Vats
I suspect Adresbound property is nullso when you try to edit the column value for binding Binding="{Binding Adres.Ulica}", it tries to set value for Adres.Ulica but Adres itself was null. Hence binding fails silently on load.
我怀疑Adresbound 属性为 null，因此当您尝试编辑 binding 的列值时Binding="{Binding Adres.Ulica}"，它会尝试为 Adres.Ulica 设置值，但 Adres 本身为 null。因此，绑定在加载时会静默失败。
You have to make sure Adresis initialized for all binded objectsso that you can edit the value for it's child property Ulicafrom dataGrid.
您必须确保Adres为所有绑定对象进行了初始化，以便您可以Ulica从 dataGrid编辑其子属性的值。
回答by dkozl
In your view model both Telefonyand Adresproperties are declared as internal. Try changing these properties to public. Check for Binding Source Types
在您的视图模型中，Telefony和Adres属性都声明为internal. 尝试将这些属性更改为public. 检查绑定源类型
You can bind to public properties, sub-properties, as well as indexers
您可以绑定到公共属性、子属性以及索引器
You've also mentioned that you can get Numerto work but in the sample code it appears to be declared as privatewhich is not valid binding source.
您还提到您可以开始Numer工作，但在示例代码中，它似乎被声明为private无效的绑定源。
回答by Syed
The problem is because of the .(dot) in the binding member name. Please refer to: Binding to fields containing a period in DataTable in C#/WPF
问题在于绑定成员名称中的 .(dot)。请参考： 绑定到C#/WPF中DataTable中包含句点的字段
