'**********************************************
'說明:將DataTable轉化為泛型集合
'名稱空間：DAL
'機器名稱：曉
'建立日期：2015/2/23 11:13:28
'作者：鄭浩
'版本號：V1.00
'**********************************************

Imports System.Collections.Generic  '增加泛型的名稱空間  
Imports System.Reflection '引入反射：為了使用PropertyInfo 
Public Class  ConvertGenericsHelper
    '將datatable轉化為泛型集合  
    Public Shared Function convertToList(Of T As {New})(ByVal dt As DataTable) As IList(Of T)
        '注意：convertToList(Of T As {New}) 這裡的new是用來約束T的，必須有，不然new T的時候會出現錯誤  

        Dim myList As New List(Of T)   '定義最終返回的集合  

        Dim myTpye As Type = GetType(T) '得到實體類的型別名  
        Dim dr As DataRow   '定義行集  

        Dim tempName As String = String.Empty   '定義一個臨時變數  

        '遍歷DataTable的所有資料行  
        For Each dr In dt.Rows

            Dim myT As New T    '定義一個實體類的物件  
            Dim propertys() As PropertyInfo = myT.GetType().GetProperties()  '定義屬性集合  
            Dim Pr As PropertyInfo

            '遍歷該物件的所有屬性  
            For Each Pr In propertys
                tempName = Pr.Name '將屬性名稱賦值給臨時變數  

                '檢查DataTable是否包含此列（列名==物件的屬性名）   
                If (dt.Columns.Contains(tempName)) Then     '將此屬性與datatable裡的列明比較，檢視datatable是否包含此屬性  
                    '判斷此屬性是否有Setter  
                    If (Pr.CanWrite = False) Then   '判斷此屬性是否可寫，如果不可寫，跳出本次迴圈  
                        Continue For
                    End If
                    Dim value As Object = dr(tempName)  '定義一個物件型的變數來儲存列的值  
                    If (value.ToString <> DBNull.Value.ToString()) Then '如果非空，則賦給物件的屬性  
                        Pr.SetValue(myT, value, Nothing)    '在執行期間，通過反射，動態的訪問一個物件的屬性  
                    End If
                End If
            Next
            myList.Add(myT)   '新增到集合  
        Next
        Return myList   '返回實體集合  
    End Function
End Class
 

 D層程式碼

'**********************************************
'說明:利用泛型集合來檢視學生餘額
'名稱空間：DAL
'機器名稱：曉
'建立日期：2015/2/23 11:27:21
'作者：鄭浩
'版本號：V1.00
'**********************************************
Imports IDAL
Imports System.Data.SqlClient
Public Class SqlserverCheckBalanceDAL : Implements ICheckBalance


    Public Function ICheckBalance(studentinfo As Entity.EN_StudentInfo) As List(Of Entity.EN_StudentInfo) Implements ICheckBalance.ICheckBalance
        Dim sql As String
        sql = "select * from ZH_StudentInfo where CardNo = @CardNo"
        Dim paras As SqlParameter() = {New SqlParameter("CardNo", studentinfo.CardNo)}
        Dim dt As New DataTable
        '儲存轉換後的泛型集合  
        Dim myList As New List(Of Entity.EN_StudentInfo)
        dt = SqlHelper.SqlHelper.ExecSelect(sql, CommandType.Text, paras)
        '先判斷dt是否為空  
        If dt.Rows.Count > 0 Then
            '將dt轉換為泛型集合  
            myList = ConvertGenericsHelper.convertToList(Of Entity.EN_StudentInfo)(dt)
            Return myList
        Else
            Return Nothing
        End If
    End Function
End Class
 

        ’直接給文字框賦值

        Dim studentinfo As New Entity.EN_StudentInfo
        studentinfo.CardNo = Trim(txtCardNo.Text)
        Dim dt As New List(Of Entity.EN_StudentInfo)
        Dim checkbalance As New Facade.FacadeCheckBalance
        dt = checkbalance.CheckBalance(studentinfo)

        txtClass.Text = dt(0).Classes  '0表示泛型集合中的第一個實體
        txtStudentNo.Text = dt(0).StudentNo
        txtName.Text = dt(0).StudentName
        txtSex.Text = dt(0).Sex
        txtStatus.Text = dt(0).Status
        txtGrade.Text = dt(0).Grade
        txtBalance.Text = dt(0).Cash
        txtExplain.Text = dt(0).Explain
    End Sub

 

  ’和DataGridView控制元件互動

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Dim studentinfo As New Entity.EN_StudentInfo
        studentinfo.CardNo = Trim(txtCardNo.Text)
        Dim dt As New List(Of Entity.EN_StudentInfo)
        Dim checkbalance As New Facade.FacadeCheckBalance
        dt = checkbalance.CheckBalance(studentinfo)

        dgvRecord.DataSource = dt
        dgvRecord.AutoGenerateColumns = True
        dgvRecord.Columns(1).HeaderText = "卡號"
    End Sub