Dim a As New SqlCommand
a.CommandText = "select * from User where ID=" & TextID.Text & "And PassWord = "& TextPassWord.Text
a.Connection = Me.SqlConnection1
Dim cmd As SqlDataReader
Me.SqlConnection1.Open()
cmd = a.ExecuteReader
If (cmd.Read) Then
MsgBox("有这条数据", , "")

Else
MsgBox("没有这条数据", , "")
End If
Me.SqlConnection1.Close()

程序运行带绿色处无法响应

[此贴子已经被作者于2007-7-8 23:42:06编辑过]

select * from User where ID=" & TextID.Text & "And PassWord = "& TextPassWord.Text

这句话应该有问题.
你的ID和PassWord都是数字型的吗？为什么不加单引号?

改成这个试试看。另外建议密码最好使用字符型

a.CommandText = "select count(*) from User where ID= '" & TextID.Text & "' And PassWord = '" & TextPassWord.Text " & "'"
a.Connection = Me.SqlConnection1
Me.SqlConnection1.Open()
Dim cont as Integer
cont = Convert.ToInt32(a.ExecuteScalar())
If count>0 Then
MsgBox("有这条数据", , "")
Else
MsgBox("没有这条数据", , "")
End If
Me.SqlConnection1.Close()

[此贴子已经被作者于2007-7-9 10:53:04编辑过]

Dim cmd As SqlDataReader
改为
Dim cmd As New SqlDataReader

应该是2楼和3楼的说法正确，4楼的明显没有经过实践

没有看懂这句： cont = Convert.ToInt32(a.ExecuteScalar())
还有就是数据类型我设置的是　text　的类型

运行之后~出错~
数据类型 text 和 varchar 在 equal to 运算符中不兼容。

用户名和密码有必要设置成text类型吗？一般都是用varchar的吧,text类型属于比较长的数据类型，在这里完全没必要，你见过8000字节的的用户名和密码吗？没有吧

如果设置了text的话应该怎么接受从数据库中返回的信息

[此贴子已经被作者于2007-7-11 14:35:44编辑过]

Dim a As New SqlCommand
a.CommandText = "select count(*) from ID='" & TextBox1.Text & "'and PassWord ='" & TextBox2.Text & "'"
a.Connection = Me.SqlConnection1
Me.SqlConnection1.Open()
Dim b As Integer
b = Convert.ToInt32(a.ExecuteScalar())
If b > 0 Then
MsgBox("有", , "")
Else
MsgBox("无", , "")
End If

Me.SqlConnection1.Close()

提示"="语法有错误~