System.invalidcastexception：指定的强制转换在VB.NET中无效 [英] System.invalidcastexception:specified cast is not valid in VB.NET

问题描述

由.Field（Of Integer）（columnname）引发的错误，请参考以下代码：

----- -------------------------------------------------- ----------------------

 DtSetBO =  New  System.Data.DataSet 
 MyCommandBO.Fill（DtSetBO）
  Dim  BOTable  As  DataTable = DtSetBO.Tables（  InvtDetailTbl ）
 
  Dim  query = From InvtDetailTbl  In  BOTable.AsEnumerable（）
 Where InvtDetailTbl.Field（ Of   String ）（  产品线）<>   
按InvtDetailTbl.Field排序（  字符串）（  MES产品 ）升序，
 InvtDetailTbl.Field（  整数）（ 收到日期时效）降序选择 InvtDetailTbl 
 
  Dim  sortedInvt  As  DataTable = query.CopyToDataTable（）
  Dim 视图 As  DataView = 新 DataView（sortedInvt） 
  Dim  sortedInvtQuery = from rowView  As  DataRowView  In 视图
 选择 rowView 
 DataGridView1.DataSource = sortedInvtQuery.ToList（）

-------------------------------------------- --------------------------------



请指教什么应该对上述问题的正确陈述。



我尝试过：



尝试 CInt，.Field（of String），.Field（of double）。

错误仍然存​​在。

解决方案

<big></big>InvtDetailTbl.Field(Of  DOUBLE ）（收到日期老化）Descending Select InvtDetailTbl 

Hi,
Error thrown due to the .Field(Of Integer)("columnname"), please refer to the following code:
-----------------------------------------------------------------------------

DtSetBO = New System.Data.DataSet
MyCommandBO.Fill(DtSetBO)
Dim BOTable As DataTable = DtSetBO.Tables("InvtDetailTbl")

Dim query = From InvtDetailTbl In BOTable.AsEnumerable()
   Where InvtDetailTbl.Field(Of String)("Product Line") <> ""
  Order By InvtDetailTbl.Field(Of String)("MES Product") Ascending,
           InvtDetailTbl.Field(Of Integer)("Received Date Ageing") Descending Select InvtDetailTbl

Dim sortedInvt As DataTable = query.CopyToDataTable()
Dim view As DataView = New DataView(sortedInvt)
Dim sortedInvtQuery = From rowView As DataRowView In view
          Select rowView
DataGridView1.DataSource = sortedInvtQuery.ToList()

----------------------------------------------------------------------------

Please advise what should the correct statement for above issue.

What I have tried:

Tried on CInt, .Field(of String), .Field(of double).
Error persist.

解决方案

<big></big>InvtDetailTbl.Field(Of DOUBLE)("Received Date Ageing") Descending Select InvtDetailTbl

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