刚刚接触语言，需要大家帮忙谢谢
登陆的界面需要验证密码，代码如下

输入用户名和密码以后，确定出现在Dr = Cm.ExecuteReader这句中：
ExecuteReader: Connection 属性尚未初始化。

请大家帮帮忙
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If Me.TextBox1.Text = " " Or Me.TextBox2.Text = " " Then
MessageBox.Show( "用户名或者密码为空! ", "警告 ")
Me.TextBox1.Text = " "
Me.TextBox2.Text = " "
Exit Sub
End If
Dim strSelectname As String
strSelectname = "select ID,PasWord from Users where (ID " & "= ' " + Me.TextBox1.Text + " ')and (pasWord= ' " + Me.TextBox2.Text + " ') "
Dim Cm As New SqlClient.SqlCommand()
Dim Dr As SqlClient.SqlDataReader
Dim strManager As String
Dim strPwd As Integer

Cm.CommandText = strSelectname
Dr = Cm.ExecuteReader
Dr.Read()
strManager = Dr.GetString(0).Trim
strPwd = Dr.GetDecimal(1)
If Me.TextBox1.Text <> strManager Or Me.TextBox2.Text <> strPwd Then
MessageBox.Show( "用户名密码错误! ")
Exit Sub
End If
Dr.Close()
FrmMain.Show()
Me.Hide()
Me.Dispose()
End Sub


[解决办法]
Dr = Cm.ExecuteReader之前
加入你的sqlconnection 比如
Dim con As New SqlConnection( "server=c-22;database=master;uid=sa;pwd=zhangln; ")
con.Open()
Cm.Connection=con

Cm.CommandText = strSelectname
Dr = Cm.ExecuteReader
Dr.Read()
...
..
Dr.Close()
con.Close()

[解决办法]
楼上正解,你搜下MSDN,(关键字为sqlconnection)看一下连接SQL Server的字符串怎么写