vb+sql学生成绩管理系统

VB与sql设计代码： Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click '选择普通用户登录 If Me.RadioButton1.Checked Then Dim str As String str = "data source=PC-201103171305\SQLEXPRESS;database=学生信息库;user id=sa;pwd=" Dim con As New SqlClient.SqlConnection(str) Try con.Open() Catch ex As Exception End Try Dim sql As String = "select * from 普通用户where 用户名='" & TextBox1.Text.ToString().Trim() & "' and 密码='" & TextBox2.Text.ToString().Trim() & " '" Dim cmd As New SqlClient.SqlCommand(sql, con) Dim reader As SqlClient.SqlDataReader Try reader = cmd.ExecuteReader If reader.Read() = True Then Dim 学生成绩管理系统As New 学生信息管理系统 学生成绩管理系统.添加DToolStripMenuItem.Enabled = False 学生成绩管理系统.修改KToolStripMenuItem.Enabled = False 学生成绩管理系统.删除DToolStripMenuItem.Enabled = False 学生成绩管理系统.添加ToolStripMenuItem.Enabled = False 学生成绩管理系统.高级用户信息管理ToolStripMenuItem.Enabled = False 学生成绩管理系统.Show() Me.Hide() Else MsgBox("对不起，用户名或密码错误！重新输入（请正确选择用户类型）", 16, "警告") Me.TextBox1.Text = "" Me.TextBox2.Text = "" TextBox1.Focus() End If Catch ex As Exception End Try End If '选择高级用户登录 If Me.RadioButton2.Checked Then Dim str As String str = "data source=PC-201103171305\SQLEXPRESS;database=学生信息库;user id=sa;pwd=" Dim con As New SqlClient.SqlConnection(str) Try con.Open() Catch ex As Exception End Try Dim sql As String = "select * from 高级用户where 用户名='" & TextBox1.Text.ToString().Trim() & "' and 密码='" & TextBox2.Text.ToString().Trim() & " '" Dim cmd As New SqlClient.SqlCommand(sql, con)