public void login_Click(object sender, EventArgs e) { string Accessfilename = @"\\注册用户表.mdb"; string Constr = "Provider=Microsoft.ace.OLEDB.12.0;Data Source=" + Application.StartupPath + Accessfilename; OleDbConnection con = new OleDbConnection(Constr); con.Open(); string selectsql1 = "Select * from UsersDat where Users='" + textBox1.Text.ToString() + "'"; string selectsql2 = "Select * from PasswordDat where password='******'"; OleDbCommand odc1 = new OleDbCommand(selectsql1, con); OleDbCommand odc2 = new OleDbCommand(selectsql2, con); OleDbDataReader odr1; OleDbDataReader odr2; odr1 = odc1.ExecuteReader(); odr2 = odc2.ExecuteReader(); if (odr1.Read() && odr2.Read()) { PaintForm paintForm = new PaintForm(); paintForm.Owner = this; paintForm.Show(); } else { MessageBox.Show("用户名或密码错误!"); return; } con.Close(); if (textBox1.Text.Trim() == "") { MessageBox.Show("用户名不能为空!"); } if (textBox2.Text.Trim() == "") { MessageBox.Show("密码不能为空!"); } }