Asp.net gridview服务器端代码与集合类绑定问题 [英] Asp.net gridview serverside code with collection class to bind problem

问题描述

大家好，这里遇到了问题.如您所见，我在应用程序代码上使用集合进行绑定.如果我的代码是这样的

Hello guys, got a problem here. As you see I am binding using collection on app code. if my code is like this one

_userDAL = New UserDAL
Dim users As UserCollection = _userDAL.SelectAll()

'Dim dr As DataTable = getTable()
gvUserList.DataSource = users
gvUserList.DataBind()

一切正常，但没有分页.现在要进行分页，我需要将其绑定到数据表上，所以这是我的代码了

everything works fine but it doesnt have paging. Now to have a paging I need to bind it on datatable so this is my code now

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
       bind()
   End Sub
   Private Sub bind()
       _userDAL = New UserDAL
       Dim users As UserCollection = _userDAL.SelectAll()

       Dim dr As DataTable = getTable()
       gvUserList.DataSource = dr
       gvUserList.DataBind()

   End Sub
   Private Function getTable() As DataTable
       _userDAL = New UserDAL
       Dim users As UserCollection = _userDAL.SelectAll()
       Dim adap As New SqlDataAdapter(users)
       Dim dt As New DataTable()
       adap.Fill(dt)
       Return dt
   End Function

但我收到一个错误消息，说''collection'' cannot be converted to sqlcommand指向用户.我知道我的逻辑是错误的，但是我找不到关于如何将GridView绑定到集合上的合适教程.你能帮我吗?

UserDAL.vb

but im getting an error saying ''collection'' cannot be converted to sqlcommand pointing at users. I know that my logic is wrong but i cant find a suitable tutorial regarding on how to bind gridview on regards to collection. Could you help me?

UserDAL.vb

Public Function SelectAll() As UserCollection
     Try
         'select * from User
         _sqlConn = New SqlConnection(_connString)
         _sqlConn.Open()

         Dim sqlCmd As New SqlCommand("select * from [Users]", _sqlConn)

         Dim dr As SqlDataReader = sqlCmd.ExecuteReader()

         'Create user collection
         Dim userColl As New UserCollection
         Dim user As User

         While dr.Read()
             'Create User object
             user = New User
             user.UserName = dr("UserName").ToString
             user.Password = dr("Password").ToString
             user.FirstName = dr("FirstName").ToString
             user.Surname = dr("Surname").ToString

             'add newley created user to collection
             userColl.Add(user)
         End While
         dr.Close()

         Return userColl

     Finally
         If _sqlConn IsNot Nothing Then
             If _sqlConn.State = Data.ConnectionState.Open Then
                 _sqlConn.Close()
             End If
         End If
     End Try
 End Function

UserCollection.vb

UserCollection.vb

Public Class UserCollection
    Inherits CollectionBase

    Public Sub Add(ByVal item As User)
        List.Add(item)
    End Sub

    Public Sub Remove(ByVal item As User)
        List.Remove(item)
    End Sub

    Default Public Property Item(ByVal index As Integer) As User
        Get
            Return DirectCast(List(index), User)
        End Get
        Set(ByVal value As User)
            List(index) = value
        End Set
    End Property

推荐答案

在您的DAL中，我应该以这种方式返回
用户列表

Hi,

In your DAL I thing you should do it this way to return the
List of User

Public Shared Function SelectAll() As List(Of User)
       ''Create List Of User
       Dim userColl As New List(Of User)
       Try
           ''select * from User
           _sqlConn = New SqlConnection(_connString)
           _sqlConn.Open()
           Dim sqlCmd As New SqlCommand("select * from [Users]", _sqlConn)
           Dim dr As SqlDataReader = sqlCmd.ExecuteReader()
           While dr.Read()
               ''Create User object
               Dim userRec As User = New User
               userRec.UserName = dr("UserName").ToString
               userRec.Password = dr("Password").ToString
               userRec.FirstName = dr("FirstName").ToString
               userRec.Surname = dr("Surname").ToString
               ''add newly created userRec to List Of User
               userColl.Add(userRec)
           End While
           dr.Close()
       Catch
           ''add something here to catch exption message ...?
       End Try
       Finally
           If _sqlConn IsNot Nothing Then
               If _sqlConn.State = Data.ConnectionState.Open Then
                   _sqlConn.Close()
               End If
           End If
       End Try
       Return userColl
   End Function

问候，

代数.

Regards,

Algem.

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