user.cs

本系统可以对某个班级的成绩进行管理

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace WindowsApplication1
{
    public partial class user : Form
    {　　  private  DataSet ds = new DataSet();
       private  SqlDataAdapter da = new SqlDataAdapter();
        public user()
        {
            InitializeComponent();
        }

        private void button11_Click(object sender, EventArgs e)
        {
            if (textBox15.Text != "" && textBox14.Text != "" && comboBox1.SelectedIndex != -1)
            {
                try
                {
                    SqlConnection myconnection = new SqlConnection();
                    myconnection.ConnectionString = "server=hxl;database=studentpoints;integrated security=true ";
                    myconnection.Open();

                    SqlCommand mycommand = new SqlCommand();
                    mycommand.CommandText = "select * from 用户表";
                   // mycommand.Connection = myconnection;
                    SqlDataAdapter da = new SqlDataAdapter();
                    da.SelectCommand = mycommand;
                    da.SelectCommand.Connection = myconnection;
                    SqlCommandBuilder cb = new SqlCommandBuilder(da);
                    DataSet ds = new DataSet();
                    da.Fill(ds, "用户表");
                    DataTable dt = ds.Tables["用户表"];
                    DataRow dr = ds.Tables["用户表"].NewRow();
                    dr["用户名"] = textBox14.Text;
                    dr["密码"] = textBox15.Text;
                    if (comboBox1.SelectedIndex == 0) dr["ID"] = 1;
                    else if (comboBox1.SelectedIndex == 1) dr["ID"] = 2;
                    else if (comboBox1.SelectedIndex == 2) dr["ID"] = 3;
                    ds.Tables["用户表"].Rows.Add(dr);
                    da.Update(ds, "用户表");
                    myconnection.Close();
                    MessageBox.Show("添加成功!");
                    textBox14.Text = ""; textBox15.Text = "";
                }
                catch (SqlException se)
                {
                    MessageBox.Show("该用户名已经存在!" + se.Message);

                }
                catch (FormatException fe)
                {
                    MessageBox.Show("输入的ID格式不正确!" + fe.Message);

                }




            }
            else
            {

                MessageBox.Show("请输入完各项数据!");

            }
        }

        private void button14_Click(object sender, EventArgs e)
        {
            if (textBox17.Text != "")
            {
                try
                {
                    SqlConnection myconnection = new SqlConnection();
                    myconnection.ConnectionString = "server=hxl;database=studentpoints;integrated security=true ";
                    myconnection.Open();

                    SqlCommand mycommand = new SqlCommand();
                    mycommand.CommandText = "select * from 用户表 where 用户名='" + textBox17.Text.Trim() + "'";
                    mycommand.Connection = myconnection;

                    da.SelectCommand = mycommand;
                    da.SelectCommand.Connection = myconnection;


                    da.Fill(ds, "用户表");
                    if (ds.Tables["用户表"].Rows.Count < 1)
                    {
                        MessageBox.Show("不存在该帐户！");

                        
                    }
                    else
                    {
                        dataGridView6.DataSource = ds.Tables["用户表"];
                        button12.Enabled = true;
                        button14.Enabled = false;
                    }
                   
                    textBox17.Text = "";
                    myconnection.Close();
                }
                catch (SqlException se)
                {
                    ds.Clear();
                    MessageBox.Show("出现错误" + se.Message);

                }
            }
            else
            {
                MessageBox.Show("请输入用户名！");

            }
        }

        private void button12_Click(object sender, EventArgs e)
        {
            {
                try
                {
                    SqlCommandBuilder cb = new SqlCommandBuilder(da);

                   da.Update(ds, "用户表");
                   ds.Clear();
                   button12.Enabled = false;
                   button14.Enabled = true;
                    MessageBox.Show("更新成功!");

                }
                catch (InvalidOperationException ie)
                {
                    MessageBox.Show("请先修改需要更改的数据！" + ie.Message);
                    ds.Clear();
                }
                catch (DBConcurrencyException de)
                {
                    MessageBox.Show("不存在该数据" + de.Message);
                    ds.Clear();
                }

            }
          
        }

        private void button15_Click(object sender, EventArgs e)
        {
            

            if (textBox17.Text != "")
            {

                try
                {



                    SqlConnection myconnection = new SqlConnection();
                    myconnection.ConnectionString = "server=hxl;database=studentpoints;integrated security=true ";
                    myconnection.Open();

                    SqlCommand mycommand = new SqlCommand();
                    mycommand.CommandText = "delete from 用户表 where 用户名='" + (textBox17.Text.Trim()) + "'";
                    mycommand.Connection = myconnection;
                    int result = mycommand.ExecuteNonQuery();
                    if (result > 0)
                        MessageBox.Show("删除成功");
                    else
                        MessageBox.Show("该用户不存在");
                    myconnection.Close();




                }
                catch (FormatException fe)
                {
                    MessageBox.Show("输入错误" + fe.Message);

                }
                catch (SqlException se)
                {
                    MessageBox.Show("出现错误!" + se.Message);

                }

                textBox17.Text = "";

            }


            else
            {

                MessageBox.Show("请输入用户名!");
            } 
        }

        private void user_Load(object sender, EventArgs e)
        {
            comboBox1.SelectedIndex = 0;
            button12.Enabled = false ;
        }

        private void button10_Click(object sender, EventArgs e)
        {
            comboBox1.SelectedIndex = -1;
            textBox14 .Text ="";
            textBox15 .Text ="";
   
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

        private void groupBox8_Enter(object sender, EventArgs e)
        {
            
        }
    }
}