grade.cs

这是用SQL数据库做的学生信息管理系统。简明

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

namespace 学生与成绩
{
	/// <summary>
	/// Grade 的摘要说明。
	/// </summary>
	public class Grade : System.Windows.Forms.Form
	{
		private DataTable myTable;
		private string sendTableName="STU";
		private string sendStrSQL;
		private DataSet ds=new DataSet();
		private CurrencyManager cmOrders;
		private LinkDataBase link=new LinkDataBase();
		private System.Windows.Forms.Label label1;
		private System.Windows.Forms.Label label2;
		private System.Windows.Forms.ComboBox comboBox1;
		private System.Windows.Forms.ComboBox comboBox2;
		private System.Windows.Forms.DataGrid dataGrid1;
		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.Button button2;
		private System.Windows.Forms.Button button3;
		/// <summary>
		/// 必需的设计器变量。
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Grade()
		{
			//
			// Windows 窗体设计器支持所必需的
			//
			InitializeComponent();

			//
			// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
			//
		}

		/// <summary>
		/// 清理所有正在使用的资源。
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if(components != null)
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows 窗体设计器生成的代码
		/// <summary>
		/// 设计器支持所需的方法 - 不要使用代码编辑器修改
		/// 此方法的内容。
		/// </summary>
		private void InitializeComponent()
		{
			this.label1 = new System.Windows.Forms.Label();
			this.label2 = new System.Windows.Forms.Label();
			this.comboBox1 = new System.Windows.Forms.ComboBox();
			this.comboBox2 = new System.Windows.Forms.ComboBox();
			this.dataGrid1 = new System.Windows.Forms.DataGrid();
			this.button1 = new System.Windows.Forms.Button();
			this.button2 = new System.Windows.Forms.Button();
			this.button3 = new System.Windows.Forms.Button();
			((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
			this.SuspendLayout();
			// 
			// label1
			// 
			this.label1.Location = new System.Drawing.Point(32, 21);
			this.label1.Name = "label1";
			this.label1.TabIndex = 0;
			this.label1.Text = "选择班级";
			this.label1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
			// 
			// label2
			// 
			this.label2.Location = new System.Drawing.Point(32, 64);
			this.label2.Name = "label2";
			this.label2.TabIndex = 1;
			this.label2.Text = "选择课程";
			this.label2.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
			// 
			// comboBox1
			// 
			this.comboBox1.Location = new System.Drawing.Point(136, 24);
			this.comboBox1.Name = "comboBox1";
			this.comboBox1.Size = new System.Drawing.Size(121, 20);
			this.comboBox1.TabIndex = 2;
			// 
			// comboBox2
			// 
			this.comboBox2.Location = new System.Drawing.Point(136, 64);
			this.comboBox2.Name = "comboBox2";
			this.comboBox2.Size = new System.Drawing.Size(121, 20);
			this.comboBox2.TabIndex = 3;
			// 
			// dataGrid1
			// 
			this.dataGrid1.DataMember = "";
			this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
			this.dataGrid1.Location = new System.Drawing.Point(20, 104);
			this.dataGrid1.Name = "dataGrid1";
			this.dataGrid1.Size = new System.Drawing.Size(248, 216);
			this.dataGrid1.TabIndex = 4;
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(15, 328);
			this.button1.Name = "button1";
			this.button1.TabIndex = 5;
			this.button1.Text = "确定";
			this.button1.Click += new System.EventHandler(this.button1_Click);
			// 
			// button2
			// 
			this.button2.Location = new System.Drawing.Point(199, 328);
			this.button2.Name = "button2";
			this.button2.TabIndex = 6;
			this.button2.Text = "保存";
			this.button2.Click += new System.EventHandler(this.button2_Click);
			// 
			// button3
			// 
			this.button3.Location = new System.Drawing.Point(107, 328);
			this.button3.Name = "button3";
			this.button3.TabIndex = 7;
			this.button3.Text = "取消";
			this.button3.Click += new System.EventHandler(this.button3_Click);
			// 
			// Grade
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
			this.ClientSize = new System.Drawing.Size(288, 366);
			this.Controls.Add(this.button3);
			this.Controls.Add(this.button2);
			this.Controls.Add(this.button1);
			this.Controls.Add(this.dataGrid1);
			this.Controls.Add(this.comboBox2);
			this.Controls.Add(this.comboBox1);
			this.Controls.Add(this.label2);
			this.Controls.Add(this.label1);
			this.Name = "Grade";
			this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
			this.Text = "成绩维护";
			this.Load += new System.EventHandler(this.Grade_Load);
			((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
			this.ResumeLayout(false);

		}
		#endregion

		private void Grade_Load(object sender, System.EventArgs e)
		{
			this.dataGrid1.CaptionText="班级成绩维护";
			
			myTable=new DataTable();
			myTable.Columns.Add("序号",typeof(char));
			myTable.Columns.Add("姓名",typeof(char));
			myTable.Columns.Add("成绩",typeof(char));
			this.dataGrid1.DataSource=myTable;
			//设置班级列表框下拉列表
			string StrConn="workstation id=localhost;Integrated Security=SSPI;database=stu01";
			SqlConnection conn=new SqlConnection(StrConn);
			conn.Open();
			SqlCommand cmd=conn.CreateCommand();
			cmd.CommandText="select distinct 班级名称 from 班级";
			SqlDataReader dr=cmd.ExecuteReader();
			while(dr.Read())
			{
				this.comboBox1.Items.Add(dr.GetValue(0).ToString().Trim());
			}
			this.GetCourseName();
		}
		//获取课程下拉列表
		private void GetCourseName()
		{
			string StrConn="workstation id=localhost;Integrated Security=SSPI;database=stu01";
			SqlConnection conn=new SqlConnection(StrConn);
			conn.Open();
			SqlCommand cmd=conn.CreateCommand();
			cmd.CommandText="select distinct 名称 from 课程表";
			SqlDataReader dr=cmd.ExecuteReader();
			while(dr.Read())
			{
				this.comboBox2.Items.Add(dr.GetValue(0).ToString().Trim());
			}
		}

		private void button1_Click(object sender, System.EventArgs e)
		{
			string courseID=this.GetCourseID();
			string classID=this.GetClassID();
			
			this.sendStrSQL="select 成绩表.序号,STU.姓名,成绩表.成绩 from STU inner join 班级 on STU.班级编号=班级.班级编号 inner join 成绩表 on STU.学号=成绩表.学号 and 班级.班级编号=成绩表.班级编号 inner join 课程表 on 成绩表.课程编号=课程表.编号"
				+" where(成绩表.班级编号='"+classID.Trim()+"') and (成绩表.课程编号='"+courseID.Trim()+"')";//关于内连接SQL语句应该注意的地方查询条件where语句中所用列名必须是sendTableName表中字段，且查询所涉及的所有表都要进行内连接，以在多表之间建立关系
         
			this.ds=link.SelectDataBase(sendStrSQL,sendTableName);
			//为数据集添加数据项浏览控制
			cmOrders=(CurrencyManager)BindingContext[ds,"STU"];
			this.dataGrid1.DataSource=ds;
			this.dataGrid1.DataMember="STU";
		}
		//课程名称和课程编号的相互转换
		private string GetCourseID()
		{
			string strConn="workstation id=localhost;Integrated Security=SSPI;database=stu01";
			SqlConnection conn=new SqlConnection(strConn);
			conn.Open();
			SqlCommand cmd=conn.CreateCommand();
			cmd.CommandText="select 编号 from 课程表 where (名称='"+this.comboBox2.Text.Trim()+"')";
			object courseID=cmd.ExecuteScalar();
			conn.Close();
			return courseID.ToString();

		}
		//班级名称和班级编号之间的相互转换
		private string GetClassID()
		{
			string strConn="workstation id=localhost;Integrated Security=SSPI;database=stu01";
			SqlConnection conn=new SqlConnection(strConn);
			conn.Open();
			SqlCommand cmd=conn.CreateCommand();
			cmd.CommandText="select 班级编号 from 班级 where (班级名称='"+this.comboBox1.Text+"')";
			object classID=cmd.ExecuteScalar();
			conn.Close();
			return classID.ToString();
		}

		private void button3_Click(object sender, System.EventArgs e)
		{
			ds.RejectChanges();
		}

		private void button2_Click(object sender, System.EventArgs e)
		{
			cmOrders.EndCurrentEdit();
			string strConn="workstation id=localhost;Integrated Security=SSPI;database=stu01";
			SqlConnection conn=new SqlConnection(strConn);
			conn.Open();
			SqlCommand cmd=conn.CreateCommand();

			for(int i=0;i<ds.Tables[0].Rows.Count;i++)
			{
				if(ds.Tables[0].Rows[i][2].ToString()=="")
					continue;
				cmd.CommandText="update 成绩表 set 成绩=cast('"+ds.Tables[0].Rows[i][2].ToString().Trim()
					+"' as int) where 序号='"+ds.Tables[0].Rows[i][0].ToString().Trim()+"'";
				cmd.ExecuteNonQuery();
			}
			conn.Close();
			MessageBox.Show(this.comboBox1.Text+this.comboBox2.Text+"成绩录入或修改完毕","提示");
		}
	}
}