使用MYSQL的VB2012注册表单
使用MYSQL的VB2012注册表单
提问于 2013-07-30 03:59:30
我试着学习用VB程序注册MYSQL。
我是新手，最近我知道如何连接到mysql并注册。
现在的问题是。我修改代码太多了，不能再注册了。
和
我想做以下几点：
1.只能注册一个唯一的用户名(输入相同用户名时显示错误)-2。用户名长度> 5，密码长度>6-3。显示寄存器完成
我只是..。迷失在某处..。需要很多帮助。谢谢。
Private Sub btnReg_Click(sender As Object, e As EventArgs) Handles btnReg.Click
Dim myAdapter As New MySqlDataAdapter
Dim myCommand As New MySqlCommand
Dim myData As MySqlDataReader
Dim add As String
Dim connect As MySqlConnection
connect = New MySqlConnection()
connect.ConnectionString = "server=localhost;user id=jackie588727;password=jackie1218;database=root"
Dim usercheck As String = "SELECT Username FROM User WHERE Username = '" + txtUser.Text + "'"
Try
connect.Open()
Catch myerror As MySqlException
MsgBox("Error connecting to database. Check your internet connection.", MsgBoxStyle.Critical)
End Try
myCommand.Connection = connect
myCommand.CommandText = usercheck
myAdapter.SelectCommand = myCommand
myData = myCommand.ExecuteReader
If myData.HasRows = 0 Then
add = "INSERT INTO user (Username, Password) VALUES('" + txtUser.Text + "','" + txtPass.Text + "')"
Else
MsgBox(txtUser.Text & " is being register, try again.", MsgBoxStyle.Information)
End If
connect.Close()
End Sub回答 2
Stack Overflow用户
回答已采纳
发布于 2013-07-30 04:05:05
更改行If myData.HasRows = 0 Then
如下所示
If not myData.HasRows ThenHasRows属性将返回true或false，如果为true，则用户已注册，您可以显示消息框，否则可以插入。
Stack Overflow用户
发布于 2013-09-14 11:11:20
我觉得你应该试试这个：
conn = New MySqlConnection("server=localhost;user id=jackie588727;password=jackie1218;database=root")
Dim username As Boolean = True
conn.Open()
Dim sqlquery As String = "SELECT * FROM TABLENAMEHERE WHERE Username = '" & TextBox1.Text & "';"
Dim data As MySqlDataReader
Dim adapter As New MySqlDataAdapter
Dim command As New MySqlCommand
command.CommandText = sqlquery
command.Connection = conn
adapter.SelectCommand = command
data = command.ExecuteReader
While data.Read()
If data.HasRows() = True Then
MsgBox("Username Already in use!")
username = False
data.Close()
Else
data.Close()
username = True
End If
End While
data.Close()
If username = True Then
Dim sqlquery2 As String = "INSERT INTO NewTable (Username, Password, Wcoins)VALUES ('" & TextBox1.Text & "','" & TextBox2.Text & "','" & "10" & "')"
Dim data2 As MySqlDataReader
Dim adapter2 As New MySqlDataAdapter
Dim command2 As New MySqlCommand
command2.CommandText = sqlquery2
command2.Connection = conn
adapter2.SelectCommand = command2
data2 = command2.ExecuteReader
MsgBox("You've Registered!")
MsgBox("Welcome " + TextBox1.Text)
My.Settings.Name = TextBox1.Text
My.Settings.Save()
Member.Show()
Me.Close()
End If如果出了什么问题，请纠正我
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原文链接：
https://stackoverflow.com/questions/17938066
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