不自动生成列时出现 WPF Datagrid 绑定(bind)错误

Question

我有一个简单的datatgrid，当我按以下方式定义它时可以工作:

    <DataGrid             
        ItemsSource="{Binding EmployeeCollectionViewSource.View}"        
        Style="{DynamicResource FTC_DataGridStyle}" AutoGenerateColumns="True" />

如果我删除 AutoGenerateColumns="True"并尝试按如下方式定义我的列，则会收到错误消息:

     <DataGrid             
        ItemsSource="{Binding EmployeeCollectionViewSource.View}"        
        Style="{DynamicResource FTC_DataGridStyle}" >
        <DataGrid.Columns>
            <DataGridTextColumn Binding="{Binding idCertification}" Header="ID" Width="50" IsReadOnly="True" CellStyle="{DynamicResource IDCellStyle}"/>
            <DataGridTextColumn Binding="{Binding chrTitle}" Header="TITLE" Width="130" CellStyle="{DynamicResource TextCellStyle}"/>
            <DataGridTextColumn Binding="{Binding chrDetail}" Header="DETAIL" Width="300" CellStyle="{DynamicResource TextCellStyle}"/>
            <DataGridTextColumn Binding="{Binding chrProvider}" Header="PROVIDER" Width="130" CellStyle="{DynamicResource TextCellStyle}"/>
        </DataGrid.Columns> />
    </DataGrid>

我得到的错误是:

{"'Add value to collection of type 'System.Windows.Controls.ItemCollection' threw an exception.' Line number '31' and line position '32'."} {"Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead."}

我使用 MVVM 模式，EmployeeCollectionViewSource 的绑定(bind)是一个 collectionviewsource，它是从实体 framemowrk 生成的 ObservableCollection 填充的。

我尝试删除列并仔细检查绑定(bind)名称，但我无法弄清楚这个错误来自哪里。输出窗口中没有显示错误。

问题
你能帮我解决这个错误，以便我可以手动定义我的列吗？

其他详细信息:
以下是我的 View 模型类:

    Public Class EmployeeCertificationViewModel
        Inherits ViewModelBase

#Region "DECLARATIONS"

        Public Const CertificationCollectionPropertyName As String = "EmployeeCertifications"
        Public Const EmployeeCollectionViewSourcePropertyName As String = "EmployeeCollectionViewSource"

        ''this is a holder for the employee data service
        Private _EmployeeAccess As IEmployeeDataService

        Private _EmployeeCertifications As New ObservableCollection(Of certification)
        Private _EmployeeCollectionViewSource As New CollectionViewSource

        ''tracks if employee validation is coming from navigation or listview selecteditemchanged
        Private FlagNavigating As Boolean = False
        Private _NavigationService As INavigationService

        Private _ModelService As IModelService
        Private Context As FTC_Context

#End Region

#Region "PROPERTIES"

        Public Property EmployeeCertifications As ObservableCollection(Of certification)
            Get
                Return Me._EmployeeCertifications
            End Get
            Set(ByVal value As ObservableCollection(Of certification))
                Me._EmployeeCertifications = value
                RaisePropertyChanged(CertificationCollectionPropertyName)
            End Set
        End Property

        Public Property EmployeeCollectionViewSource As CollectionViewSource
            Get
                Return Me._EmployeeCollectionViewSource
            End Get
            Set(value As CollectionViewSource)
                If _EmployeeCollectionViewSource Is value Then
                    Return
                End If
                _EmployeeCollectionViewSource = value
                RaisePropertyChanged(EmployeeCollectionViewSourcePropertyName)
            End Set
        End Property


#End Region

#Region "COMMANDS"

#End Region

#Region "METHODS"

#End Region

#Region "CONSTRUCTOR"
        Public Sub New(NavService As INavigationService, EmployeeService As IEmployeeDataService, ModelService As IModelService)

            _ModelService = ModelService
            Context = _ModelService.NewContext

            _NavigationService = NavService
            _EmployeeAccess = EmployeeService

            EmployeeCertifications = EmployeeService.Get_Certification(Context)
            EmployeeCollectionViewSource.Source = EmployeeCertifications

        End Sub

#End Region

    End Class

Answer 1

DataGrid.AutoGenerateColumns Property是 真实 默认情况下。如果要定义自己的列，则必须明确将其设置为 false。否则，您将同时拥有两种列类型(自动生成和自己定义)。

<DataGrid ItemsSource="{Binding}" AutoGenerateColumns="False">
    <DataGrid.Columns>
        ...
    </DataGrid.Columns>
</DataGrid>

但你真正的问题似乎是额外的 /> 在 </DataGrid.Columns> 之后在你的代码中。删除它，异常应该消失。