最后一本书 第五章上机练习1-4

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

namespace 最后一本书_第五章上机
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
} DataSet ds = new DataSet();
public string s = "Data Source=.;Initial Catalog=MySchool;Integrated Security=True";
public void getGrade() {

MySchool.DBHelper db = new MySchool.DBHelper();
string sql = "select * from Grade";
SqlDataAdapter adapter = new SqlDataAdapter(sql,db.Connection);
adapter.Fill(ds,"Grade");
//foreach(DataRow row in ds.Tables[0].Rows){
//    Console.WriteLine("{0}   \t {1}",row["GradeId"],row["GradeName"]);

//}
this.comboBox1.DataSource = ds.Tables["Grade"];
this.comboBox1.ValueMember = "GradeId";
this.comboBox1.DisplayMember = "GradeName";

DataRow row = ds.Tables["Grade"].NewRow();
row["GradeId"] = -1;
row["GradeName"] = "全部";
ds.Tables["Grade"].Rows.InsertAt(row,0);
}

private void Form1_Load(object sender, EventArgs e)
{
getGrade();
SearchStudent();
}

private void button1_Click(object sender, EventArgs e)
{
//getGrade();
SearchStudent();
//string s = this.comboBox1.SelectedValue.ToString();
//string d = this.comboBox1.Text;
//MessageBox.Show("内容" + s + "实际" + d, "提示");

}

private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
{

}
public void SearchStudent() {
MySchool.DBHelper s = new MySchool.DBHelper();
try
{
string sql="select * from student";
if (!this.comboBox1.Text.Equals("全部"))
{
sql += " where GradeId=" + this.comboBox1.SelectedValue;
}
SqlDataAdapter adapter = new SqlDataAdapter(sql,s.Connection);

if (ds.Tables["Student"] != null)
{
ds.Tables["Student"].Clear();
}
adapter.Fill(ds,"Student");
}
catch (Exception e)
{
MessageBox.Show(e.Message);

}
this.dataGridView1.AutoGenerateColumns = false;
this.dataGridView1.DataSource = ds.Tables["Student"];
}

private void 保存_Click(object sender, EventArgs e)
{
MessageBox.Show("确认要修改么？", "提示", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
MySchool.DBHelper s = new MySchool.DBHelper();
string sql = "select * from student";
SqlDataAdapter adapter = new SqlDataAdapter(sql,s.Connection);
SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
adapter.Update(ds, "Student");
}

private void 查询IdToolStripMenuItem_Click(object sender, EventArgs e)
{

}

private void 添加学生成绩ToolStripMenuItem_Click(object sender, EventArgs e)
{ MySchool.DBHelper s = new MySchool.DBHelper();
MessageBox.Show(this.dataGridView1.SelectedCells[0].Value.ToString(),"提示");

}
}
}