首先，要了解完成学生管理系统的步骤：
总共有几个模块，我就逐一讲解：
完成登录页面模块：
判断“登录”是否成功的代码：
1 private void btnLogin_Click(object sender, EventArgs e)
2 {
3 string str = DBHelper.str;
4 SqlConnection con = new SqlConnection(str);
5 string sql = "select count(1) from student where studentname='" + txtnamea.Text + "' and loginpwd='" + txtpwdtu.Text + "' ";
6 SqlCommand cmd = new SqlCommand(sql,con);
7 con.Open();
8 int count = Convert.ToInt32(cmd.ExecuteScalar());
9 if (count > 0)
10 {
11 //MessageBox.Show("登陆成功");
12 this.Hide();
13 //Welcome frm = new Welcome();
14
15 //frm.name= txtnamea.Text;
16 //frm.Show();
17 }
18 con.Close();
19 //用户名，密码和登录类型都不能为空
20 if (CheckInput())
21 {
22 //显示系统管理员主窗体
23 //隐藏登录窗体
24 this.Hide();
25 }
26 FrmAdminMain frm = new FrmAdminMain();
27 //方法1：
28 //frm.pwd=txtpwdtu.Text;
29 //方法2:
30 Tool.pwd = txtpwdtu.Text;
31 frm.Show();
32 }
1 if (this.txtnamea.Text.Trim().Equals(string.Empty))
2 {
3 MessageBox.Show("请输入用户名", caption, MessageBoxButtons.OK, MessageBoxIcon.Information);
4 this.txtnamea.Focus();
5 return false;
6 }
7 else if (this.txtpwdtu.Text.Trim().Equals(string.Empty))
8 {
9 MessageBox.Show("请输入密码", caption, MessageBoxButtons.OK, MessageBoxIcon.Information);
10 this.txtpwdtu.Focus();
11 return false;
12 }
13 else if (this.cboLoginType.Text.Trim().Equals(string.Empty))
14 {
15 MessageBox.Show("请输入登录类型", caption, MessageBoxButtons.OK, MessageBoxIcon.Information);
16 this.cboLoginType.Focus();
17 return false;
18 }
19 else
20 {
21 return true;
22 }
修改密码的窗体：
修改密码的代码：
1 private void FrmChangePwd_Load(object sender, EventArgs e)
2 {
3 //颜色变化
4 this.BackColor = Color.Red;
5 //显示旧密码到就文本框里面
6 txtoldpwd.Text = Tool.pwd;
7 }
8
9 private void btnqueren_Click(object sender, EventArgs e)
10 {
11 string num = txtnewpwd.Text;
12 string str = DBHelper.str;
13
14 string sql = "update student set loginpwd='" + num + "' where loginpwd='" + txtoldpwd.Text + "'";
15 SqlConnection con = new SqlConnection(str);
16 SqlCommand cmd = new SqlCommand(sql, con);
17 con.Open();
18 if (txtconfrimpwd.Text.Equals(num))
19 {
20 int com = Convert.ToInt32(cmd.ExecuteScalar());
21 }
22
23 DialogResult result = MessageBox.Show("确定要修改密码吗？","温馨提示",MessageBoxButtons.YesNo,MessageBoxIcon.Question);
24 if (result==DialogResult.Yes)
25 {
26 this.Close();
27 }
28 con.Close();
制作管理员窗体：
怎样做才使“窗体跳转”的代码：
//选择"新增学生"时打开"编辑学生信息"窗体
private void 编辑学生信息ToolStripMenuItem_Click(object sender, EventArgs e)
{
FrmEditStudent frm = new FrmEditStudent();
frm.MdiParent = this;
frm.Show();
}
private void 退出ToolStripMenuItem_Click(object sender, EventArgs e)
{
DialogResult result = MessageBox.Show("确认要退出吗?", "温馨提示", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (result == DialogResult.Yes)
{
this.Close();
}
}
//选择“窗口”中的查询学生时显示的“窗体”
private void 查询学生信息ToolStripMenuItem_Click(object sender, EventArgs e)
{
FrmSearchByName frm = new FrmSearchByName();
frm.MdiParent = this.MdiParent;
frm.Show();
}
//选择“帮助”中的”关于“时显示的窗体
private void 关于ToolStripMenuItem_Click(object sender, EventArgs e)
{
FrmAbout frm = new FrmAbout();
frm.MdiParent = this.MdiParent;
frm.Show();
}
private void 修改密码ToolStripMenuItem_Click(object sender, EventArgs e)
{
FrmChangePwd frm = new FrmChangePwd();
frm.MdiParent = this.MdiParent;
//让修改密码前，给其pwd赋值
//frm.pwd = pwd;
frm.Show();
}
private void toolStripDropDownButton1_Click_2(object sender, EventArgs e)
{
FrmEditStudent frm = new FrmEditStudent();
frm.MdiParent = this.MdiParent;
frm.Show();
}
private void toolStripDropDownButton2_Click(object sender, EventArgs e)
{
FrmSearchByName frm = new FrmSearchByName();
frm.MdiParent = this.MdiParent;
frm.Show();
编辑学生窗体：
怎么样才能得到所有“年级名称”的代码：
1 //加载年级到下拉框信息
2 public void LoadGrade() {
3
4 //拿到所有年级名称
5 string str = DBHelper.str;
6 SqlConnection con = new SqlConnection(str);
7 string sql = "select gradename from grade";
8 SqlCommand cmd = new SqlCommand(sql, con);
9
10 con.Open();
11 SqlDataReader dr = cmd.ExecuteReader();
12
13 if (dr != null)
14 {
15 if (dr.HasRows)
16 {
17 while (dr.Read())
18 {
19 string gname = dr["gradename"].ToString();
20 //将年级放到下拉框中
21 cbograde.Items.Add(gname);
22 }
23 }
24 }
拿到所有“学生信息”的代码：
1 //通过学生学号更改信息
2 public void LoadStudentbyStudentno() {
3 string str = DBHelper.str;
4 SqlConnection con = new SqlConnection(str);
5
6 string sql = "select *from student where studentno=" + studentNo + "";
7 SqlCommand cmd = new SqlCommand(sql,con);
8
9 try
10 {
11 con.Open();
12 SqlDataReader dr = cmd.ExecuteReader();
13 //一列拆解,复制到当前的文本框
14 while (dr.Read())
15 {
16 //获取名字
17 string stuname = dr["studentname"].ToString();
18 txtname.Text = stuname;
19 //获取电话
20 string stuphone = dr["phone"].ToString();
21 txtphone.Text = stuphone;
22 //获取地址
23 string stuadress = dr["address"].ToString();
24 txtadress.Text = stuadress;
25 //获取邮件
26 string stuemail= dr["email"].ToString();
27 txtemail.Text = stuemail;
28 ////获取密码
29 //string strpwd=dr["LoginPwd"].ToString();
30 //txtpwd.Text = strpwd;
31 ////确认密码
32 //txttruepwd.Text = strpwd;
33 //获取出生日期
34 DateTime day =Convert.ToDateTime( dr["birthday"]);
35 cbobirthdatetime.Value = day;
36 //获取年级名称
37 int getid = Convert.ToInt32(dr["gradeid"]);
38 string gradename = GetidName(getid);
39 cbograde.Text = gradename;
40 //获取性别
41 string genders=dr["gender"].ToString();
42 if (genders.Equals("0"))
43 {
44 rbtnFemale.Checked = true;
45 }
46 if(genders.Equals("1")) {
47
48 rbtnMale.Checked = true;
49 }
50
将“年级编号”转化为“年级名称”的代码：
1 //将年级编号转换为年级名称
2 public string GetidName(int getid)
3 {
4 string str = DBHelper.str;
5 SqlConnection con = new SqlConnection(str);
6
7 string sql = "select gradename from grade where gradeid=" + getid + "";
8 SqlCommand cmd = new SqlCommand(sql, con);
9 string getname = "";
10 try
11 {
12 con.Open();
13 getname = cmd.ExecuteScalar().ToString();
14 }
15 catch (Exception)
16 {
17
18 }
19 finally
20 {
21 con.Close();
22 }
23 return getname;
当你点击“修改”的时候，”编辑窗体“变为“修改信息的窗体”的代码：
1 private void FrmEditStudent_Load(object sender, EventArgs e)
2 {
3 LoadGrade();
4 //当点修改按钮时,变成修改窗体
5 if (studentNo != 0)
6 {
7 this.Text = "修改学生信息";
8 btnsave.Text = "修改";
9 }
10 else {
11 this.Text = "编辑学生信息";
12 btnsave.Text = "保存";
13 }
14
15 txtnano.Text = studentNo.ToString();
16 LoadStudentbyStudentno();
17 }
修改“学生信息”的代码：
1 public void updateInfo() {
2 //修改密码
3 string pwd = txtpwd.Text;
4 //修改姓名
5 string studentname = txtname.Text;
6 //修改性别
7 string studentgender = string.Empty;
8 if (rbtnFemale.Checked)//女
9 {
10 studentgender = "0";
11 }
12 else if (rbtnMale.Checked)//男
13 {
14 studentgender = "1";
15 }
16 //如何给下拉框绑定数据
17 int getid = GetIdByName();
18 //修改电话
19 string phone = txtphone.Text;
20 //修改地址
21 string adrers = txtadress.Text;
22 //修改日期
23 DateTime birthdate = this.cbobirthdatetime.Value;
24 //修改邮件
25 string emailt = txtemail.Text;
26 string sql =string.Format("update student set loginpwd='{0}',studentname='{1}',gender='{2}',gradeid='{3}',phone='{4}',address='{5}',birthday='{6}',email='{7}' where studentno={8}", pwd, studentname, studentgender, getid, phone, adrers, birthdate, emailt,studentNo);
27 string str = DBHelper.str;
28 SqlConnection con = new SqlConnection(str);
29 SqlCommand cmd = new SqlCommand(sql, con);
30 con.Open();
31 int count = cmd.ExecuteNonQuery();
32 if (count>0)
33 {
34 //调用查询窗口的一个DataSelect()方法
35 frmselectInfo.DataSelect();
36 MessageBox.Show("修改成功");
37 }
38 else
39 {
40 MessageBox.Show("失败");
41 }
1 //根据学号是否为0，判定该按钮用来执行“添加”还是“修改”
2 if (studentNo != 0)
3 {
4 //修改
5 updateInfo();
6 }
7 else
8 {
9 //添加
10 AddStudent();
11 }
将“年级名称”变为“年级名称”的代码：
1 //该方法将年级名称转换成年级编号
2 public int GetIdByName()
3 {
4 string str = DBHelper.str;
5 SqlConnection con = new SqlConnection(str);
6 string sql = "select gradeid from grade where gradename='" + cbograde.Text + "'";
7 SqlCommand cmd = new SqlCommand(sql, con);
8 int getid = 0;
9 try
10 {
11 con.Open();
12 getid = Convert.ToInt32(cmd.ExecuteScalar());
13 }
按姓名查询学生信息的窗体：
查询和在Load事件中提前显示的代码：
1 private void FrmSearchByName_Load(object sender, EventArgs e)
2 {
3 //在Load事件中编写代码提前显示
4 //查询
5 string sql = @"select Studentno,Studentname,Gender,gradename
6 from student,grade
7 where student.gradeid=grade.gradeid ";
8 LoadFrmListView(sql);
9 }
10 //查询数据
11 public void DataSelect()
12 {
13 lvlistview.Items.Clear();
14 string sql = @"select studentno,studentname,Gender,gradename from student,grade
15 where student.gradeid=grade.gradeid and studentname like '%" + txtsearchname.Text + "%'";
16 LoadFrmListView(sql);
17 }
获取学号的代码：
1 private void 修改ToolStripMenuItem_Click(object sender, EventArgs e)
2 {
3
4 if (this.lvlistview.SelectedItems.Count > 0)
5 {
6 FrmEditStudent frm = new FrmEditStudent();
7 //将选中的学号传递到"编辑学生信息窗体"
8 //frm.studentNo = Convert.ToInt32(this.lvlistview.SelectedItems[0].Text);也可以
9 frm.studentNo = Convert.ToInt32(this.lvlistview.SelectedItems[0].SubItems[0].Text);
10 frm.MdiParent = this.MdiParent;
11 frm.frmselectInfo = this;
12 frm.Show();
获取学生信息的代码：：
1 //获取学号 2 int stuNo = Convert.ToInt32(dr["studentno"]); 3 //第二列获取姓名 stuname 4 string stuName = Convert.ToString(dr["studentname"]); 5 //第三列 获取 性别 6 string stugender = Convert.ToString(dr["gender"]); 7 //获取年级名称 8 string gname = Convert.ToString(dr["gradename"]); 9 // 10 ListViewItem lvItem = new ListViewItem(stuNo.ToString()); 11 lvItem.SubItems.Add(stuName);//接收学生名字 12 lvItem.SubItems.Add(stugender);//接收学生性别 13 lvItem.SubItems.Add(gname);//接收学生年级名称 14 //让lvItem和ListView关联 15 lvlistview.Items.Add(lvItem); 16 }
关于我们的窗体：
计时器的Tick事件处理方法，定时变换图片框中的图片代码：
1 private void timetime_Tick(object sender, EventArgs e)
2 {
3 //如果当前显示的图片索引没有到最大值就继续增加
4 if (index < imglist.Images.Count - 1)
5 {
6 index++;
7 }
8 else {
9 index = 0;
10 }
11 //设置图片框显示的图片
12 this.pictureBox1.Image = imglist.Images[index];
按年级查询学生信息的的窗体：
加载年级的代码：
1 //加载年级信息
2 public void LoadGradeInfo() {
3
4 //创建数据库连接
5 string str = DBHelper.str;
6 SqlConnection con = new SqlConnection(str);
7 //string sql = "select studentno,studentname,gender,birthday from student";
8 string sql = "select gradeid,gradename from Grade";
9 SqlDataAdapter da = new SqlDataAdapter(sql, con);
10 DataSet ds = new DataSet();
11 da.Fill(ds,"Grade");
12 DataRow row =ds.Tables["Grade"].NewRow();
13 row[0]=-1;
14 row[1] = "全部";
15 ds.Tables["Grade"].Rows.InsertAt(row,0);
16
17 cbograde.DataSource = ds.Tables["Grade"];
18 //ValueMember下拉框显示的隐藏值
19 cbograde.ValueMember = "gradeid";
20 //DisplayMember下拉框显示的真实值
21 cbograde.DisplayMember = "Gradename";
22 cbograde.SelectedIndex = 0;
23 }
修改的代码：
1 //保存修改
2 private void btnSAve_Click(object sender, EventArgs e)
3 {
4 DialogResult result = MessageBox.Show("确定要修改吗？",caption,MessageBoxButtons.YesNo,MessageBoxIcon.Question);
5 if (result==DialogResult.Yes)//确认保存修改
6 {
7 //使用SqlCommandBuilder构建增删改的command操作
8 SqlCommandBuilder sq = new SqlCommandBuilder(da);
9 //将数据集中student表的数据交给数据库更新
10 da.Update(ds, "student");
11 }
删除信息的窗体：
获取信息代码：
1 public void FillTables(){
2 string str = DBHelper.str;
3 //取消英文列自动生成,就是没写列名称时，不能用英文列代替
4 dgstudenlist.AutoGenerateColumns = false;
5 SqlConnection con = new SqlConnection(str);
6 string sql = "select studentno,studentname,gender,gradename,phone from student,grade where student.gradeid=grade.gradeid";
7 SqlDataAdapter da = new SqlDataAdapter(sql, con);
8 DataSet ds = new DataSet();
9 da.Fill(ds, "student");
10 this.dgstudenlist.DataSource = ds.Tables["student"];
11 }
12 private void FrmStudentList_Load(object sender, EventArgs e)
13 {
14 FillTables();
15 }
删除操作的代码：
1 //确认删除操作
2 DialogResult result = MessageBox.Show("确认删除改学生吗？同时会删除该学生的成绩！！！", "提示", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
3 if (result == DialogResult.Yes)
4 {
5 if (dgstudenlist.SelectedRows.Count > 0)
6 {
7 //获得选中的学生的学号
8 int studentno = Convert.ToInt32(dgstudenlist.SelectedRows[0].Cells["studentno"].Value);
9 }
10 string str = DBHelper.str;
11 SqlConnection con = new SqlConnection(str);
12 string sql = string.Format("delete from result where studentno={0}", StudentNO);
13 con.Open();
14 SqlCommand cmd = new SqlCommand(sql, con);
15 int count = cmd.ExecuteNonQuery();
16 //删除学生信息
17 sql = string.Format("delete from student where studentno={0}", StudentNO);
18 cmd.CommandText = sql;
19 int result1 = cmd.ExecuteNonQuery();
20 if (result1 == 1)
21 {
22 MessageBox.Show("删除成公！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
23 //重新查询数据，绑定数据源，重新帅选
24 FillTables();
25 }
26 con.Close();
其中一些重要代码：
1.向数据集年级表的第一行添加数据“全部”或者“请选择”的代码:
1 1 DataRow row = ds.Tables["Grade"].NewRow();//形成行对象 2 2 row["gradeid"] = -1;//给该行的列赋值 3 3 row["gradename"] = "全部"; 4 4 ds.Tables["Grade"].Rows.InsertAt(row, 0);//行对象和Table产生关系 5 5 6 6 7 7 或者 8 8 9 9 //01.形成行对象 table.NewRow() 10 10 DataTable table = ds.Tables[0]; 11 11 DataRow dr=table.NewRow(); 12 12 //02.给该行的列赋值 dr[0]=-1; 13 13 dr[0] = -1; 14 14 dr[1] = "请选择"; 15 15 //03.让行对象和Table产生关系table.Rows.InsertAt() 16 16 table.Rows.InsertAt(dr,0);
2.向下拉框赋值，即年级名称，隐藏年级编号:
1 SqlDataAdapter da = new SqlDataAdapter(sql, con); 2 DataSet ds = new DataSet(); 3 da.Fill(ds, "Grade"); 4 cbograde.DataSource = ds.Tables["Grade"]; 5 //ValueMember下拉框显示的隐藏值gradeid 6 cbograde.ValueMember = "gradeid"; 7 //DisplayMember下拉框显示的真实值Gradename 8 cbograde.DisplayMember = "Gradename"; 9 cbograde.SelectedIndex = 0; //索引为0 10 con.Close();