C#实现学生模块的增删改查

本文实例为大家分享了c#实现学生模块的增删改查的具体代码，供大家参考，具体内容如下

using system;using system.collections.generic;using system.componentmodel;using system.data;using system.data.sqlclient;using system.drawing;using system.linq;using system.text;using system.threading.tasks;using system.windows.forms;namespace text3_crud{  public partial class form1 : form  {    //把连接数据库的字符串提取出来，就不用每次都要写，增加代码复用性    private string str = "data source=本地ip;initial catalog=数据库名;ur id=用户名;pwd=密码";    public form1()    {      initializecomponent();     }       private void textbox5_textchanged(object nder, eventargs e)    {    }    private void form1_load(object nder, eventargs e)    {    }    private void label10_click(object nder, eventargs e)    {    }    /// <summary>    /// 添加学生信息档案    /// </summary>    /// <param name="nder"></param>    /// <param name="e"></param>    private void butadd_click(object nder, eventargs e)    {      //获取各个文本框的数据      string name = txtname.text;      string x = txtx.text;      string college = txtcollege.text;      string id = txtid.text;      string grade = txtgrade.text;      string phone = txtphone.text;      string email = txtemail.text;      string qq = txtqq.text;      string room = txtroom.text;      using (var conn = new sqlconnection(this.str))//定义一个数据库连接实例      {        conn.open();//打开数据库               form1 f = new form1();//实例化form1窗体对象        if (f.existence(id, conn))//检查数据库 存不存在此条记录，存在则插入        {          sqlparameter[] para = new sqlparameter[]//构建存储过程的输入参数          {            new sqlparameter("@name",name),            new sqlparameter("@x", x),            new sqlparameter("@college", college),            new sqlparameter("@id", id),            new sqlparameter("@grade", grade),            new sqlparameter("@phone", phone),            new sqlparameter("@email", email),            new sqlparameter("@qq", qq),            new sqlparameter("@room", room),          };          string sql = "inrt into students values(@name, @x, @college, @id, @grade, @phone, @email, @qq, @room);";//定义一个数据库操作指令集          sqlcommand com = new sqlcommand(sql, conn);//执行数据库操作指令          com.parameters.addrange(para);//將参数和命令对象的参数集合绑定          int result = (int)com.executenonquery();//针对connection执行的sql语句，返回受影响的行数，result > 0则表示sql语句执行成功          if (result > 0)          {            messagebox.show("添加成功！");//弹窗显示“添加成功”            this.form1_load_1(null, null);//刷新数据                     }          el          {            messagebox.show("添加失败！");          }                 }        el        {          messagebox.show("数据已经存在！");        }        conn.clo();//关闭数据库        //application.exit();//关闭整个应用程序      }    }    /// <summary>    /// 根据id值判断数据表students中是否存在这个人，存在返回fal，不存在返回true    /// </summary>    /// <param name="id"></param>    /// <param name="conn"></param>    /// <returns></returns>    public bool existence(string id, sqlconnection conn)    {      string txtstr = string.format( "lect id from students where id = '{0}' " ,id);//定义一个数据库操作指令集      sqldataadapter sda = new sqldataadapter(txtstr, conn);//定义一个数据库适配器      datat ds = new datat();//定义数据集合      sda.fill(ds);//填充数据集合      datatable dt = ds.tables[0];//將数据集合中的第一张表赋值给datatable      if(dt.rows.count > 0)  //count > 0表示有数据      {        return fal;      }      el      {        return true;      }         }    /// <summary>    /// 对数据库进行的动态查询，不管用户掌握的信息有多少都可以查询    /// </summary>    /// <param name="nder"></param>    /// <param name="e"></param>    private void btnlect_click(object nder, eventargs e)    {      //获取各个文本框的数据      string name = txtname.text;      string x = txtx.text;      string college = txtcollege.text;      string id = txtid.text;      string grade = txtgrade.text;      string phone = txtphone.tadvertiment可数吗ext;      string email = txtemail.text;      string qq = txtqq.text;      string room = txtroom.text;      using(var conn = new sqlconnection(this.str))//定义一个数据库连接实例      {        conn.open();//打开数据库        stringbuilder sb = new stringbuilder();//创建一个字符串变量        sb.append("lect name, x, college, id, grade,phone, email, qq, room from students where 1=1");        //判断用户有没有给出其它的查询条件，有则添加进sql语句        if (name != "")        {          sb.appendformat(" and name = '{0}'", name);        }        if (x != "")        {          sb.appendformat(" and x = '{0}'", x);        }        if (college != "")        {          sb.appendformat(" and college = '{0}'", college);        }        if (id != "")        {          sb.appendformat(" and id = '{0}'", id);        }        if (grade != "")        {          sb.appendformat(" and grade = '{0}'", grade);        }        if (phone != "")        {          sb.appendformat(" and phone = '{0}'", phone);        }        if (email != "")        {          sb.appendformat(" and email = '{0}'", email);        }        if (qq != "")        {          sb.appendformat(" and qq = '{0}'", qq);        }        if (room != "")        {          sb.appendformat(" and room = '{0}'", room);        }        string sql = sb.tostring();        sqldataadapter adapter = new sqldataadapter(sql, conn);        datat ds = new datat();//定义一个数据集合        adapter.fill(ds);//填充数据集合        datagridview1.datasource = ds.tables[0];//把数据集合绑定到datagridview上，datagridview会以表格的形式显示出来        conn.clo();//关闭数据库      }    }    /// <summary>  会计事务所实习心得  /// 修改学生信息    /// </summary>    /// <param name="nder"></param>    /// <param name="e"></param>    private void btnupdate_click(object nder, eventargs e)    {      //获取各个文本框的数据      string name = txtname.text;      string x = txtx.text;      string college = txtcollege.text;      string id = txtid.text;      string grade = txtgrade.text;      string phone = txtphone.text;      string email = txtemail.text;      string qq = txtqq.text;      string room = txtroom.text;      //构建存储过程的输入参数      sqlparameter[] para = new sqlparameter[]      {        new sqlparameter("@name",name),        new sqlparameter("@x", x),        new sqlparameter("@college", college),        new sqlparameter("@id", id),        new sqlparameter("@grade", grade),        new sqlparameter("@phone", phone),        new sqlparameter("@email", email),        new sqlparameter("@qq", qq),        new sqlparameter("@room", room)      };      using(var conn = new sqlconnection(this.str))      {        conn.open();//打开数据库；        string sql = "update students t name = @name, x = @x, college = @college, id = @id, grade = @grade, phone = @phone, email = @email, qq = @qq, room = @room where id = @id";        sqlcommand com = new sqlcommand(sql, conn);//执行数据库操作指令        com.parameters.addrange(para);//将参数和命令对象的参数集合绑定        int result = (int)com.executenonquery();//查询返回的第一行第一列        if(result > 0)        {          messagebox.show("修改成功！");          this.form1_load_1(null, null);//修改完数据后，重新刷新属性form1窗口，以查看变化的内容          conn.clo();//关闭数据库        }      }      //sqldataadapter sda = new sqldataadapter();    }    /// <summary>    /// 刷新datagridview里的数据    /// </summary>    /// <param name="nder"></param>    /// <param name="e"></param>    private void form1_load_1(object nder, eventargs e)    {           using (var conn = new sqlconnection(this.str))//定义一个数据库连接实例      {        conn.open();//打开数据库        string sql = "lect * from students";//定义一个数据库操作指令        sqldataadapter sda = new sqldataadapter(sql, conn);//定义数据库适配器        datat ds = new datat();//定义数据集合        sda.fill(ds);//填充数据集合        datagridview1.datasource = ds.tables[0];        conn.clo();//关闭数据库      }    }    private void datagridview1_cellclick(object nder, datagridviewcelleventargs e)    {         }    /// <summary>    /// 选中datagridview的行，这一行的数据返回到对应的文本框    /// </summary>大专以上学历;    /// <param name="nder"></param>    /// <param name="e"></param>    private void datagridview1_cellclick_1(object nder, datagridviewcelleventargs e)    {       //lectedrows[0] 获取用户选定行的集合(选中的第一行就是0，一次类推)      //cells["name"] 获取用于填充行的单元格集合(就是列) .value就是它的值,最后tostring转字符串      txtname.text = datagridview1.lectedrows[0].cells["name"].value.tostring();      txtx.text = datagridview1.lectedrows[0].cells["x"].value.tostring();      txtcollege.text = datagridview1.lectedrows[0].cells["college"].value.tostring();      txtid.text = datagri中国四大名校dview1.lectedrows[0].cells["id"].value.tostring();      txtgrade.text = datagridview1.lectedrows[0].cells["grade"].value.tostring();      txtphone.text = datagridview1.lectedrows[0].cells["phone"].value.tostring();      txtemail.text = datagridview1.lectedrows[0].cells["email"].value.tostring();      txtqq.text = datagridview1.lectedrows[0].cells["qq"].value.tostring();      txtroom.text = datagridview1.lectedrows[0].ce如何画正方体lls["room"].value.tostring();    }    /// <summary>    /// 删除某个学生的所有数据    /// </summary>    /// <param name="nder"></param>    /// <param name="e"></param>    private void btndelete_click(object nder, eventargs e)    {      using(var conn = new sqlconnection(this.str))//创建一个数据库连接实例      {        conn.open();//连接数据库        string sql = string.format("delete from students where id = '{0}'", txtid.text);//往数据库操作指令中传值        //如果传的值不是很多的话，就用这种方法；如果有很多就用sqlparameter[]        sqlcommand com = new sqlcommand(sql, conn);//执行数据库删除指令        int result = (int)com.executenonquery();//返回结果，result > 0则为修改成功        if(result > 0)        {          messagebox.show("删除成功！");          this.form1_load_1(null, null);//刷新数据          conn.clo();//关闭数据库        }      }    }    /// <summary>    /// 对文本框进行清空处理，方便重新输入下一个学生信息    /// </summary>    /// <param name="nder"></param>    /// <param name="e"></param>    private void btnclear_click(object nder, eventargs e)    {      txtname.text = null;      txtx.text = null;      txtcollege.text = null;      txtid.text = null;      txtgrade.text = null;      txtphone.text = null;      txtemail.text = null;      txtqq.text = null;      txtroom.text = null;    }  }}

students表

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