From 9723016b4f4ae90b798673aa2903b28d8057ce0e Mon Sep 17 00:00:00 2001
From: aufe20202437 <aufe20202437@qq.com>
Date: Tue, 22 Nov 2022 09:19:05 +0800
Subject: [PATCH] Update README.md

---
 README.md | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 2479ea7..f06cc1c 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,51 @@
-# LibraryManagementSystem
-
+// 用户登录代码实现：主要通过sql语句调用DataAccess类中的GetDataSetBySql()方法来实现的
+namespace L019_BookMange
+{
+    public partial class frmLogin : Form
+    {
+        public frmLogin()
+        {
+            InitializeComponent();
+        }
+        private void btnLogin_Click(object sender, EventArgs e)
+        {
+            //输入账号密码正确          
+            if (Validate())
+            {
+                string state = this.cboUserType.Text;
+               int num;
+                if (state.Equals("管理员"))//判断用户角色，若为管理员
+                    num = 2;
+                else  //若为读者
+                    num = 1;
+                //定义查询语句
+                string sql = string.Format("select * from userinfo where uname='{0}'and upwd='{1}'and ustate={2}", this.txtName.Text.Trim(), this.txtPwd.Text.Trim(), num);
+                DataSet ds = DataAccess.GetDataSetBySql(sql); //操作数据库
+                if (ds.Tables[0].Rows.Count > 0)
+                {
+                    MessageBox.Show("登录成功");
+                    FrmMain.result = DialogResult.OK;//为变量result赋值
+                    this.Close();
+                }
+                else
+                    MessageBox.Show("用户名或密码错误，请重新输入");
+            }           
+        }
+        private void frmLogin_Load(object sender, EventArgs e)
+        {
+            this.cboUserType.SelectedIndex = 0;
+        }
+        private bool Validate() //检测用户名和密码是否为空
+        {
+            if (this.txtName.Text != string.Empty && this.txtPwd.Text != string.Empty)
+                return true;
+            else
+                MessageBox.Show("用户名或密码不能为空"); //返回错误提示信息
+            return false;
+        }
+        private void btnCancle_Click(object sender, EventArgs e)
+        {
+            this.Close();
+        }
+    }
+}
\ No newline at end of file