Question

我已在表格中声明这些是私人的。

Private callLogConnection As New OleDbConnection()
Private schDataAdapter = New OleDbDataAdapter("Select * From tbl_schtime", _ callLogConnection)
Private schCommmandBuilder = New OleDbCommandBuilder(schDataAdapter)
Private schDataTable As New DataTable
Private schRowPosition As Integer = 0
Private qryexceptionDataAdapter = New OleDbDataAdapter("Select * From  _ qry_exceptionUpdate", callLogConnection)
Private exceptionBindingSource = New BindingSource()
Private exception2BindingSource As New BindingSource
Private exceptionCommandBuilder As OleDbCommandBuilder = New _ OleDbCommandBuilder(qryexceptionDataAdapter)
Private qryexceptionDataTable As New DataTable
Private qryexceptionRowPostiion As Integer = 0
Private tbl_ExceptionDataSet As DataSet = New DataSet
Private exceptionDataTable As New DataTable

我已在表单load

中声明了这些对象

qryexceptionDataAdapter.Fill(qryexceptionDataTable)
'linking the qryexception table to binding source
exceptionBindingSource.DataSource = qryexceptionDataTable
'showing the binding source in the datagrid view
dgvExceptions.DataSource = exceptionBindingSource

这是我的保存按钮命令，用于从datagridview更新我的表。

Private Sub btnSaveException_Click(sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveException.Click
    Try
        Me.Validate()
        Me.qryexceptionDataAdapter.Update(Me.tbl_ExceptionDataSet.Tables("qry_exceptionUpdates"))
        Me.tbl_ExceptionDataSet.AcceptChanges()
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try

    End Sub code here

但我一直在接受：

System.Reflection.AmbiguousMatchException: Overload resolution failed because no Public 'Update' is most specific for these arguments:
    'Public Function Update(dataTable As System.Data.DataTable) As Integer':
        Not most specific.
    'Public Overrides Function Update(dataSet As System.Data.DataSet) As Integer':
        Not most specific.
    'Public Function Update(dataRows As System.Data.DataRow()) As Integer':
        Not most specific.
   at Microsoft.VisualBasic.CompilerServices.OverloadResolution.ResolveOverloadedCall(String MethodName, List`1 Candidates, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, BindingFlags LookupFlags, Boolean ReportErrors, ResolutionFailure& Failure)
   at Microsoft.VisualBasic.CompilerServices.OverloadResolution.ResolveOverloadedCall(String MethodName, MemberInfo[] Members, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, BindingFlags LookupFlags, Boolean ReportErrors, ResolutionFailure& Failure)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.ResolveCall(Container BaseReference, String MethodName, MemberInfo[] Members, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, BindingFlags LookupFlags, Boolean ReportErrors, ResolutionFailure& Failure)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.CallMethod(Container BaseReference, String MethodName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack, BindingFlags InvocationFlags, Boolean ReportErrors, ResolutionFailure& Failure)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.ObjectLateCall(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack, Boolean IgnoreReturn)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateCall(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack, Boolean IgnoreReturn)
   at Call_Log.CallLogForm.btnSaveException_Click(Object sender, EventArgs e) in C:\Users\mdutton\Desktop\Call Log\Call Log\CallLogForm.vb:line 174

Answer 1

线索在你的调用堆栈中：

Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateCall。

这意味着VB试图找出它应该在运行时调用哪个重载而不是设计时。被抛出的异常最有可能意味着：

Me.tbl_ExceptionDataSet.Tables("qry_exceptionUpdates")

评估为Nothing，因为有3个重载采用了可能与您的请求匹配的单个对象参数（为您帮助列出的异常）。

所以，这里有两件事需要解决：

1）在项目属性中设置Option Strict On。来自Microsoft Documentation：

除了禁止隐式缩小转化之外，还有选项   严格为后期绑定生成错误。对象是后期绑定的   当它被赋值给声明为类型的变量时   对象

因为Option Strict On提供强类型，可以防止意外   输入数据丢失的转换，禁止后期绑定，并改进   性能，强烈建议使用它。

2）完成上述操作后，仍然会出现运行时错误，但现在DataTable参数不能为null（Nothing），因此您也需要修复它。

您的示例代码中可能有拼写错误，但按钮点击事件中的表名与您在select语句中的表名不匹配（qry_exceptionUpdates vs _qry_exceptionUpdate）。

如果可能，您应该在全局或模块级常量中指定一次表名，这样就不会遇到这种类型的命名问题。

vb 2010，删除datagridview中的行以更新访问表

1 个答案: