用数据表中的数据填充对象属性. [英] Filling object attributes with data from a data table.

问题描述

我已经完成了一个类和一个用类对象填充数据库的函数
以及删除对象的功能.现在需要一种用于修改对象的解决方案.这意味着从数据库修改对象返回对象并保存修改后的对象.这就是为什么需要一个函数来用数据库中的数据填充对象属性的原因.谢谢！

I have done a class and a function for populating database with objects of class
and also a function for deleting objects. Now a need a solution for modifying objects. that means returning object from database modifying it and save it modified. That''s why a need a function that fill object attributes with data from database. Thank you !

Imports System.Data
Imports System.Data.Sql
Imports System.Data.SqlClient
Imports System.Data.SqlTypes
Public Class Salariat
    Dim m_cnp As String
    Dim m_nume As String
    Dim m_prenume As String
    Dim m_adresa As String
    Dim m_telefon As String
    Dim m_calificare As String
    Dim m_contBancar As String

    Public Property cnp() As String
        Get
            Return m_cnp
        End Get
        Set(ByVal value As String)
            If Len(value) = 13 Then
                m_cnp = value
            Else
                Throw New Exception("CNP incorect!")
            End If
        End Set
    End Property
    Public Property nume() As String
        Get
            Return m_nume
        End Get
        Set(ByVal value As String)
            If value <> "" Then
                m_nume = value
            Else
                Throw New Exception("Completati Numele!")
            End If

        End Set
    End Property
    Public Property prenume() As String
        Get
            Return m_prenume
        End Get
        Set(ByVal value As String)
            If value <> "" Then
                m_prenume = value
            Else
                Throw New Exception("Completati Prenumele!")
            End If

        End Set
    End Property
    Public Property adresa() As String
        Get
            Return m_adresa
        End Get
        Set(ByVal value As String)
            m_adresa = value
        End Set
    End Property
    Public Property telefon() As String
        Get
            Return m_telefon
        End Get
        Set(ByVal value As String)
            m_telefon = value
        End Set
    End Property
    Public Property calificare() As String
        Get
            Return m_calificare
        End Get
        Set(ByVal value As String)
            m_calificare = value
        End Set
    End Property
    Public Property contBancar() As String
        Get
            Return m_contBancar
        End Get
        Set(ByVal value As String)
            If Len(value) = 24 Then
                m_contBancar = value
            Else
                Throw New Exception("Cont bancar incorect!")
            End If
        End Set
    End Property
    Public Sub Adauga()
        Dim cmd As New SqlCommand
        Dim sCnnection As String = "server=(local);Integrated Security=SSPI;database=crossal"
        Dim cnn As New SqlConnection With {.ConnectionString = sCnnection}
        cnn.Open()
        cmd.Connection = cnn
        cmd.CommandText = "INSERT INTO salariati (CNP, Nume, Prenume, Adresa, Telefon, Calificare, Contbancar) VALUES (@CNP, @Nume, @Prenume, @Adresa, @Telefon, @Calificare, @Contbancar)"
        cmd.Parameters.AddWithValue("@CNP", Me.cnp)
        cmd.Parameters.AddWithValue("@Nume", Me.nume)
        cmd.Parameters.AddWithValue("@Prenume", Me.prenume)
        cmd.Parameters.AddWithValue("@Adresa", Me.adresa)
        cmd.Parameters.AddWithValue("@Telefon", Me.telefon)
        cmd.Parameters.AddWithValue("@Calificare", Me.calificare)
        cmd.Parameters.AddWithValue("@ContBancar", Me.contBancar)
        cmd.ExecuteNonQuery()
    End Sub
    Public Sub Sterge(ByVal pcnp)
        Dim qq
        qq = MsgBox("Doriti sa stergeti salariatul cu CNP-ul " & pcnp & " ?", MsgBoxStyle.YesNo)
        If qq = vbYes Then
            Dim cmd As New SqlCommand
            Dim sCnnection As String = "server=(local);Integrated Security=SSPI;database=crossal"
            Dim cnn As New SqlConnection With {.ConnectionString = sCnnection}
            cnn.Open()
            cmd.Connection = cnn
            cmd.CommandText = " delete from salariati where cnp=''" + pcnp + "''"
            cmd.ExecuteNonQuery()
        Else
        End If
    End Sub
    Public Sub Incarca(ByVal pcnp)
        Dim ccnp As New SqlCommand
        Dim sConnection As String = "server=(local);Integrated Security=SSPI;database=Salarizare"
        Dim c As New SqlConnection(sConnection)
        c.Open()
        ccnp.Connection = c
        ccnp.CommandText = " select * from salariati where cnp=''" + pcnp + "''"

    End Sub
End Class

推荐答案

要执行此操作，您将需要2种方法.一个返回正确的对象，另一个返回修改后的对象，如下所示:

To do this you will need 2 methods. One that returns the correct object, and another to save the object once it has been modified like this:

Public Function GetSalariat(ByVal pcnp) As Salariat

        Dim sConnection As String = "server=(local);Integrated Security=SSPI;database=Salarizare"
        Dim c As New SqlConnection(sConnection)
        Try
            Dim ccnp As New SqlCommand
            c.Open()
            ccnp.Connection = c
            'don't use * in SQL Query - better to list all fields you need by name
            ccnp.CommandText = "SELECT cnp, nume, prenume etc FROM salariati WHERE cnp = @cnp"
            ccnp.Parameters.AddWithValue("@cnp", pcnp)
            Dim drSalariats As SqlDataReader = ccnp.ExecuteReader()
            Dim newSalariat As New Salariat()
            While drSalariats.Read()
                newSalariat.cnp = drSalariats.GetInt32(0)
                newSalariat.nume = drSalariats.GetString(1)
                newSalariat.prenume = drSalariats.GetString(2)
                'add rest of members here
            End While
            Return newSalariat
        Catch ex As SqlException
            Throw ex 'should be handled better
        Finally
            If c.State = ConnectionState.Open Then
                c.Close()
            End If
        End Try

    End Function

并保存:

and to save:

Public Shared Function SaveSalariat(ByVal salariatToSave As Salariat) As Integer

        Dim sCnnection As String = "server=(local);Integrated Security=SSPI;database=crossal"
        Dim cnn As New SqlConnection With {.ConnectionString = sCnnection}
        Try
            Dim cmd As New SqlCommand
            cnn.Open()
            cmd.Connection = cnn
            cmd.CommandText = "UPDATE tableName Set Nume = @Nume, PreNume = @Prenume, etc WHERE cnp = @Cnp"
            cmd.Parameters.AddWithValue("@Nume", salariatToSave.nume)
            cmd.Parameters.AddWithValue("@PreNume", salariatToSave.prenume)
            'add rest of parameters here
            Return cmd.ExecuteNonQuery()
        Catch ex As SqlException
            Throw ex 'should be handled better
        Finally
            If cnn.State = ConnectionState.Open Then
                cnn.Close()
            End If
        End Try

    End Function

希望对您有帮助

Hope this helps

这篇关于用数据表中的数据填充对象属性.的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！