C#复习提纲.docx

1、C#复习提纲1、从键盘读入一个字符串，赋给变量i int x = Convert.ToInt32(Console.ReadLine()；2、 /将字符串转换为整型数据 int x = Convert.ToInt32(i);3、/foreach p34 foreach (int index in list.Keys) Console.WriteLine(index + t + listindex)；4、数组 p471) 定义：int, b = new int3, 5;2) 长度： for (int i = 0; i b.GetLength(0); i+) 3) 二维数组中，没有的元素，不显示，可

2、以空着 【b0 = new string2 b11, b12 ;】【b1 = new string3 b21, b22, b23 ;】 【b2 = new string5 a, e, i, o, u ;】4) 数组调整长度：【 String myArr = fox, lazy, dog ;【 Array.Resize(ref myArr, myArr.Length + 2);5) 数组的排序函数：【Array.Sort(books);/升序函数【Array.Reverse(books);/降序函数【books.Contains(C#) ;/包含函数【Array.IndexOf(books, C

3、#);/元素在数组中的位置6）将数组中的元素转换为字符static string GetStrings(int a) string s = new stringa.Length; for (int i = 0; i a.Length; i+) si = ai.ToString(); return s; 7）数组函数：int a = 10, 20, 4, 8 ;【 a.Average()【 a.Sum()【 a.Max()【 a.Min()5、字符 p42【 string.Join(, colorNames)；/将各个字符用“，”连接【 string str = string.Format( 6

4、、泛型 p54-55public static void Swap(ref T item1, ref T item2) T temp = item1; item1 = item2; item2 = temp; 7、列表 p57 【List list = new List(); 8、时间 p61【DateTime now = DateTime.Now;【string str = string.Format( 0:现在是yyyy年M月d日，H点m分,dddd, now);9、数学函数 Math p62SuperCombine：using System;using System.Collection

5、s.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.IO;using System.Data.SqlClient;namespace WindowsFormsApplication1 public partial class SuperCombine : Form public SuperCombine() InitializeComponen

6、t(); /目录的创建事件 private void btnCreateDir_Click(object sender, EventArgs e) try if (!txtPath.Text.Equals() string str = txtPath.Text.Trim(); Directory.CreateDirectory(str); MessageBox.Show(成功创建目录); else MessageBox.Show(请重新输入要建的目录！); catch (Exception ex) throw(ex); /文件创建的事件 private void btnCreateFile_C

7、lick(object sender, EventArgs e) try if (!txtPath.Text.Equals() string str = txtPath.Text.Trim(); File.Create(str); MessageBox.Show(成功创建文件!); else MessageBox.Show(请重新输入要创建文件！); catch (Exception ex) throw (ex); /打开并显示某个目录下的所有文件的事件 private void btnOpen_Click(object sender, EventArgs e) if (folderBrows

8、erDialog1.ShowDialog() = DialogResult.OK) textBox1.Text = folderBrowserDialog1.SelectedPath; string path = textBox1.Text.Trim(); if (!Directory.Exists(path) MessageBox.Show(文件夹不存在!); return; string files = Directory.GetFiles(path); for (int i = 0; i files.Length; i+) string tmp = Path.GetFileName(fi

9、lesi); listBox1.Items.Add(tmp); /打开所选的文件里的内容 private void listBox1_MouseDoubleClick(object sender, MouseEventArgs e) string file = listBox1.SelectedItem.ToString(); file = textBox1.Text.Trim() + + file; string ext = Path.GetExtension(file); if (ext.ToLower() = .txt) richTextBox1.Text = File.ReadAllT

10、ext(file); else MessageBox.Show(请选择txt文件); /combox控件的操作 private void btnShow_Click(object sender, EventArgs e) try /数据库连接部分 string con = server=localhost;uid=sa;pwd=as;database=db_course; SqlConnection sqlcon = new SqlConnection(con); /提取数据库中的内容放入适配器，再放入datatable中 string SQL = select sno from studen

11、t; SqlDataAdapter da = new SqlDataAdapter(SQL, con); DataTable dt = new DataTable(); /适配器里的数据填充入dt中 da.Fill(dt); comboBox1.Items.Clear(); for (int i = 0; i 0) MessageBox.Show(操作成功！?, 提示); fileOpration_Load(null,null); catch (Exception ex) throw (ex); private void btnDelete_Click(object sender, Event

12、Args e) string strSql = ; strSql = delete from student where sno= + txtSNo.Text + and sname= + txtSName.Text + ; try string con = server=localhost;uid=sa;pwd=as;database=db_course; SqlConnection sqlcon = new SqlConnection(con); SqlCommand cmd = new SqlCommand(strSql, sqlcon); sqlcon.Open(); cmd.Exec

13、uteNonQuery(); sqlcon.Close(); MessageBox.Show(删除成功！, 提 示); fileOpration_Load(null, null); catch (Exception ex) throw (ex); /string strSql = update(Sno,sname,sage) values( + txtSNo.Text + , + txtSName.Text + , + txtSAge + , + ); 文件的操作 private void button2_Click(object sender, EventArgs e) string pat

14、h1 = e:temp; string files = Directory.GetFiles(path1); for (int i = 0; i files.Length; i+) string dirName = Path.GetDirectoryName(filesi); string extName = Path.GetExtension(filesi); string fileNameNoExt = Path.GetFileNameWithoutExtension(filesi); fileNameNoExt = (Convert.ToInt32(fileNameNoExt).ToSt

15、ring();/去掉数字前面的“0 【fileNameNoExt = fileNameNoExt.PadLeft(3,0);】 string fileName = dirName + + fileNameNoExt + extName; File.Move(filesi, fileName); /能够使文件显示 /for/流水线插入学号 string con = server=localhost;uid=sa;pwd=as;database=Renee; SqlConnection sqlcon = new SqlConnection(con); /执行查询到最大的学号 string strS

16、ql1 = select max(sno) from testSno; SqlCommand com1 = new SqlCommand(strSql1,sqlcon); sqlcon.Open(); /执行查询，并返回查询所返回的结果集中的第一行的第一列，忽略其他行和列 string value = com1.ExecuteScalar().ToString(); sqlcon.Close(); /截取后四位 string strLF=value.Substring(4,4); int numLF = Convert.ToInt32(strLF);/转换为int numLF+; /拼接字符串

17、 string newLF = Convert.ToString(numLF).PadLeft(4, 0); /解决convert.ToInt32,填充0 string Last = value.Substring(0, 4) + newLF; /插入数据库 string strSql2 = insert into testSno(sno) values( + Last + ) ; sqlcon.Open(); SqlCommand com2 = new SqlCommand(strSql2, sqlcon); com2.ExecuteNonQuery(); sqlcon.Close(); /

18、over MessageBox.Show(Last);/实现学号位数的扩充，如从0-999到0-9999的扩充 string con = server=localhost;uid=sa;pwd=as;database=Renee; SqlConnection sqlcon = new SqlConnection(con); /执行查询到最大的学号 string strSql1 = select * from testSno; SqlCommand com1 = new SqlCommand(strSql1, sqlcon); sqlcon.Open(); string value = com1

19、.ExecuteScalar().ToString(); sqlcon.Close(); SqlDataAdapter sda = new SqlDataAdapter(strSql1, sqlcon); DataTable dt = new DataTable(); sda.Fill(dt); for (int i = 0; i dt.Rows.Count; i+) int id =Convert.ToInt32( dt.Rowsiid); string strRg = dt.Rowsisno.ToString().Substring(0, 4); string strLF = dt.Row

20、sisno.ToString().Substring(4, 4); string temp = strRg + 0 + strLF; /插入数据库 string strSql2 = update testSno set sno=+temp+ where id=+id+; sqlcon.Open(); SqlCommand com2 = new SqlCommand(strSql2, sqlcon); com2.ExecuteNonQuery(); sqlcon.Close(); 删除当前行private void 删?除yToolStripMenuItem_Click(object sende

21、r, EventArgs e) try int row = dataGridView1.CurrentRow.Index; if (row 0) return; string sno = dataGridView1sno, row.Value.ToString(); DialogResult result = MessageBox.Show(确_实害_删?除y学号?为a + sno.Trim() + 的?记?录?吗e？?,询问信?息,MessageBoxButtons.YesNo,MessageBoxIcon.Question); if (result = DialogResult.No) r

22、eturn; string sql = delete from student where sno=+ sno +; DBTOOL.SqlCmdOperation(sql); MessageBox.Show(删?除y成功|！?); catch (Exception ex) MessageBox.Show(ex.Message); 删除选中行private void toolStripMenuItem2_Click(object sender, EventArgs e) /删?除y选?中D行D try if (dataGridView1.SelectedRows.Count = 0) MessageBox.Show(您还1没?有瓺选?中D行D！?); return; DialogResult result = MessageBox.Show(确_实害_删?除y吗e？?, 询问信?息, Message