VB.NET 2010：错误“ErrorExecuteReader：连接属性尚未初始化”
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VB.NET 2010: Error "ErrorExecuteReader: Connection property has not been initialized"
提问by beginnerVB.Net
I'm getting this error: "ErrorExecuteReader: Connection property has not been initialized"
我收到此错误： "ErrorExecuteReader: Connection property has not been initialized"
I can't figure out what the problem is.
我无法弄清楚问题是什么。
Imports System.Boolean
Imports System.Data.SqlClient
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim userID As String
Dim password As String
Dim conn As SqlConnection
Dim cmd As SqlCommand
Dim reader As SqlDataReader
userID = txtuser.Text
password = txtpassword.Text
txtuser.Text = Focus()
txtpassword.Visible = "False"
Try
conn = New SqlConnection("Data Source=XXXXXX;Initial Catalog=XXXXXXUser ID=XXXXXX;Password=XXXXXX")
cmd = New SqlCommand("Select user,password from userlog where user='" + userID + "' & password='" + password + "'")
conn.Open()
reader = cmd.ExecuteReader()
conn.Close()
If (String.Compare(password, 123) = 0) Then
MsgBox("Success")
End If
Catch ex As Exception
MsgBox("Error" + ex.Message())
End Try
End Sub
End Class
回答by anon
The connection property of your command object hasn't been set. Add it to your constructor like so:
您的命令对象的连接属性尚未设置。将它添加到您的构造函数中，如下所示：
cmd = New SqlCommand("...", conn)
Or set the Connection property like so:
或者像这样设置 Connection 属性：
cmd.Connection = conn
By the way, this error should have been easy to catch if you were debugging in Visual Studio.
顺便说一下，如果您在 Visual Studio 中进行调试，这个错误应该很容易被发现。
