Question

我正在为visual studio 2012中的更新功能编码，但是，有一个“invalidcastexception未处理”错误。

这是windows窗体中更新功能的编码：

Private Sub btnupdate_Click(sender As Object, e As EventArgs) Handles btnupdate.Click
        ClassSiswa.Nis = txt_nis.Text
        ClassSiswa.Nisn = txt_nisn.Text
        ClassSiswa.Jenis_Kelamin = cmb_kelaminsiswa.Text
        ClassSiswa.Kota_Lahir = txt_kotalahir.Text
        ClassSiswa.Tanggal_Lahir = DTP_siswa.Text
        ClassSiswa.Agama = cmb_agamasiswa.Text
        ClassSiswa.Berat_Badan = txt_beratsiswa.Text
        ClassSiswa.Tinggi_Badan = txt_tinggi_badan.Text
        ClassSiswa.EditData(ClassSiswa.opencon, txt_nis.Text)
        MessageBox.Show(" Data Telah Diupdate")
        ClassKoneksi.closecon()
        datagridview()

    End Sub

这是函数的类：

Public Class ClassSiswa
    Inherits ClassKoneksi

    Private Shared _Nis, _Nisn, _Berat_Badan, _Tinggi_Badan As Integer
    Private Shared _Nama_Siswa, _Jenis_Kelamin, _Kota_Lahir, _Agama As String
    Private Shared _Tanggal_Lahir As Date
    Public Shared Property Nis() As Integer
        Get
            Return _Nis
        End Get
        Set(ByVal value As Integer)
            _Nis = value
        End Set
    End Property
    Public Shared Property Nisn() As Integer
        Get
            Return _Nisn
        End Get
        Set(ByVal value As Integer)
            _Nisn = value
        End Set
    End Property
    Public Shared Property Berat_Badan() As Integer
        Get
            Return _Berat_Badan
        End Get
        Set(ByVal value As Integer)
            _Berat_Badan = value
        End Set
    End Property
    Public Shared Property Tinggi_Badan() As Integer
        Get
            Return _Tinggi_Badan
        End Get
        Set(ByVal value As Integer)
            _Tinggi_Badan = value
        End Set
    End Property
    Public Shared Property Nama_Siswa() As String
        Get
            Return _Nama_Siswa
        End Get
        Set(ByVal value As String)
            _Nama_Siswa = value
        End Set
    End Property
    Public Shared Property Jenis_Kelamin() As String
        Get
            Return _Jenis_Kelamin
        End Get
        Set(ByVal value As String)
            _Jenis_Kelamin = value
        End Set
    End Property
    Public Shared Property Kota_Lahir() As String
        Get
            Return _Kota_Lahir
        End Get
        Set(ByVal value As String)
            _Kota_Lahir = value
        End Set
    End Property
    Public Shared Property Tanggal_Lahir() As Date
        Get
            Return _Tanggal_Lahir
        End Get
        Set(ByVal value As Date)
            _Tanggal_Lahir = value
        End Set
    End Property
    Public Shared Property Agama() As String
        Get
            Return _Agama
        End Get
        Set(ByVal value As String)
            _Agama = value
        End Set
    End Property

    Public Shared Sub EditData(ByVal _cn As SqlClient.SqlConnection, ByVal Nis As Integer)
        Dim sql As New SqlClient.SqlCommand
        sql.Connection = _cn
        sql.CommandType = CommandType.Text = "update siswa set Nis ='" & Nisn & "',Nama_Siswa='" & Nama_Siswa & "',Jenis_Kelamin='" & Jenis_Kelamin & "',Kota_Lahir='" & Kota_Lahir & "',Tanggal_Lahir='" & Tanggal_Lahir & "',Agama='" & Agama & "',Berat_Badan='" & Berat_Badan & "',Tinggi_Badan='" & Tinggi_Badan & "'where Nis='" & Nis & "'"
        ClassSiswa.cmd.ExecuteNonQuery()
        sql.ExecuteNonQuery()
    End Sub

这是SQL查询：

Create Database KPIRWAN
use KPIRWAN

Create Table siswa 
(
Nis int,
Nisn int,
Nama_Siswa varchar(40),
Jenis_Kelamin varchar (10),
Kota_Lahir varchar (10),
Tanggal_Lahir date,
Agama varchar (10),
Berat_Badan int,
Tinggi_Badan int)

问题是：在btnupdate编码中，当我试图更新数据时，表示错误说 “从字符串”“转换为”整数“类型无效”for：

ClassSiswa.Nis = txt_nis.Text

或

从字符串“”到“日期”类型的转换对以下内容无效：

ClassSiswa.Tanggal_Lahir = DTP_siswa.Text

如何修复此错误？

Answer 1

您的所有数据都是来自文本框的字符串......您需要根据需要强制它们，因此如果您需要整数，则需要使用CInt(txt_nis.Text) ... 您可能还需要CDate作为日期等。除非您在验证客户端，否则您可能还需要考虑验证值，例如..

    If IsNumeric(txt_nis.Text) Then
        'value is numeric and can be assigned to ClassSiswa.Nis using CInt(txt_nis.Text)
    Else
        'value is not numeric handle error
    End If

您可以使用IsDate

查看日期

在Visual Basic 2012 OOP方法中更新功能

1 个答案: