1. 设计一个Windows登陆窗体应用程序，能够实现根据现有表中数据模拟登陆，并设置相关属性，具体界面如下。

可能使用到的类：

（1）SqlConnection

（2）SqlCommand

（3）SqlDataReader

（4）MessageBox

 1 using System; 2 using System.Collections.Generic; 3 using System.ComponentModel; 4 using System.Data; 5 using System.Drawing; 6 using System.Linq; 7 using System.Text; 8 using System.Windows.Forms; 9 using System.Data.SqlClient;10 11 namespace Myform12 {13 public partial class Form1 : Form14  {15 public Form1()16  {17  InitializeComponent();18  }19 20 21 private void button1_Click(object sender, EventArgs e)22  {23 24 string connString = @"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\C#09J20172202899何海钊\Myform\Myform\Database1.mdf;Integrated Security=True;User Instance=True";25 SqlConnection conn = null;26 SqlCommand cmd = null;27 SqlDataReader reader = null;28 try29  {30 conn = new SqlConnection(connString);31  conn.Open();32 cmd = conn.CreateCommand();33 cmd.CommandText = "Select username , password From Table1 where username = ‘com201701‘ and password = ‘com201701‘";34 cmd.Parameters.AddWithValue("@username", textBox1.Text.Trim());35 cmd.Parameters.AddWithValue("@password", textBox2.Text.Trim());36 reader = cmd.ExecuteReader();37 if (reader.Read())38  {39 MessageBox.Show("登录成功", "OK", MessageBoxButtons.OK, MessageBoxIcon.Information);40  }41 else42  {43 MessageBox.Show("用户名密码不正确", "NO", MessageBoxButtons.OK, MessageBoxIcon.Error);44  }45 46  }47 catch (Exception ex)48  {49 MessageBox.Show(ex.Message, "Open Error", MessageBoxButtons.OK);50  }51 finally 52  {53 if (reader != null) reader.Close();54 if (conn.State == ConnectionState.Open) conn.Close();55  }56  }57  }58 }

Code1

2、设计一个Windows登陆窗体应用程序，根据下图设置相关属性，该程序能够读写现有表中数据，具体界面如下。

 1 using System; 2 using System.Collections.Generic; 3 using System.ComponentModel; 4 using System.Data; 5 using System.Drawing; 6 using System.Linq; 7 using System.Text; 8 using System.Windows.Forms; 9 using System.Data.SqlClient;10 11 namespace Myform212 {13 public partial class Form1 : Form14  {15 public Form1()16  {17  InitializeComponent();18  }19 20 private SqlConnection conn = null;21 private SqlCommand cmd = null;22 private SqlDataReader reader = null;23 private SqlDataAdapter adapter = null;24 private DataSet List = null;25 26 private string connString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=D:\C#09J20172202899何海钊\db\Database1.mdf;Integrated Security=True;Connect Timeout=30";27 28 private void button1_Click(object sender, EventArgs e)29  {30 try31  {32 conn = new SqlConnection(connString);33  conn.Open();34 cmd = conn.CreateCommand();35 cmd.CommandText = "Insert into Table1 ( username , password ) values (@username , @password ) ";36 cmd.Parameters.AddWithValue("@username", textBox1.Text.Trim());37 cmd.Parameters.AddWithValue("@password", textBox2.Text.Trim());38 int n = cmd.ExecuteNonQuery();39 if ( n > 0 )40  {41 MessageBox.Show("成功插入", "Insert OK ", MessageBoxButtons.OK, MessageBoxIcon.Information);42  }43 else44  {45 MessageBox.Show("插入失败", "Insert error", MessageBoxButtons.OK, MessageBoxIcon.Error);46  }47 48  }49 catch (Exception ex)50  {51 MessageBox.Show(ex.Message, "Open Error", MessageBoxButtons.OK);52  }53 finally54  {55 if (reader != null) reader.Close();56 if (conn.State == ConnectionState.Open) conn.Close();57  }58  }59 60 private void button2_Click(object sender, EventArgs e)61  {62 try63  {64 conn = new SqlConnection(connString);65  conn.Open();66 cmd = conn.CreateCommand();67 cmd.CommandText = "Select * From Table1 ";68 69 adapter = new SqlDataAdapter(cmd);70 71 List = new DataSet();72 73  adapter.Fill(List);74 DataTable table = List.Tables[0];75 76 DataRowCollection Rows = table.Rows;77 78 for (int i = 0; i < Rows.Count; i++)79  {80 DataRow row = Rows[i];81 string username = (string)row["username"];82 string password = (string)row["password"];83 84 this.richTextBox1.Text += username + " " + password + "\r\n";85  }86  }87 catch (Exception ex)88  {89 MessageBox.Show(ex.Message, "Open Error", MessageBoxButtons.OK);90  }91 finally92  {93 if (reader != null) reader.Close();94 if (conn.State == ConnectionState.Open) conn.Close();95  }96  }97  }98 }

Code2

3、设计一个Windows窗体应用程序，根据下图设置相关属性，该程序能够读取AdventureWorksDW_Data.mdf数据库中DimReseller表中数据，具体界面如下。

 1 using System; 2 using System.Collections.Generic; 3 using System.ComponentModel; 4 using System.Data; 5 using System.Drawing; 6 using System.Linq; 7 using System.Text; 8 using System.Threading.Tasks; 9 using System.Windows.Forms; 10 using System.Data.SqlClient; 11  12 namespace FormPage 13 { 14 public partial class Form1 : Form 15  { 16  17  18 private SqlConnection conn = null; 19 private SqlCommand cmd = null; 20 private SqlDataAdapter adapter = null; 21 private SqlDataReader reader = null; 22 private DataSet ds = null; 23  24 private int pageSize = 10; 25 private int rowCount = 0; 26 private int pageNum = 0; 27 private string connectString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=D:\C#09J20172202899何海钊\MyForm3\AdventureWorksDW2008\AdventureWorksDW_Data.mdf;Integrated Security=True;Connect Timeout=30"; 28  29 public Form1() 30  { 31  InitializeComponent(); 32  Count_Row(); 33  Fill_Data(); 34  } 35  36 private void btn_FirstPage_Click(object sender, EventArgs e) 37  { 38 pageNum = 0; 39  Fill_Data(); 40  } 41  42  43 private void btn_LastPage_Click(object sender, EventArgs e) 44  { 45 pageNum = rowCount/pageSize; 46  Fill_Data(); 47  } 48  49 private void btn_PrePage_Click(object sender, EventArgs e) 50  { 51 if( pageNum > 0 ) 52  { 53 pageNum--; 54  Fill_Data(); 55  } 56  } 57  58 private void btn_NextPage_Click(object sender, EventArgs e) 59  { 60 if (pageNum < rowCount / pageSize) 61  { 62 pageNum++; 63  Fill_Data(); 64  } 65  66  } 67 private void btn_Fill_Click(object sender, EventArgs e) 68  { 69  Fill_Data(); 70  } 71 void Fill_Data() 72  { 73 if (pageNum == 0) 74  { 75 btn_FirstPage.Enabled = false; 76 btn_PrePage.Enabled = false; 77  } 78 else 79  { 80 btn_FirstPage.Enabled = true; 81 btn_PrePage.Enabled = true; 82  } 83  84 if( pageNum == rowCount / pageSize) 85  { 86 btn_LastPage.Enabled = false; 87 btn_NextPage.Enabled = false; 88  } 89 else 90  { 91 btn_LastPage.Enabled = true; 92 btn_NextPage.Enabled = true; 93  } 94 try 95  { 96 conn = new SqlConnection(connectString); 97  conn.Open(); 98  99 cmd = conn.CreateCommand();100 cmd.CommandText = "Select top ("+pageSize+ ") Employeekey , FirstName , LastName , EmailAddress , Phone from DimEmployee where EmployeeKey not in( Select top (" + pageSize *pageNum+ ") EmployeeKey from DimEmployee order by EmployeeKey ) order by EmployeeKey";101 102 103 104 ds = new DataSet();105 adapter = new SqlDataAdapter(cmd);106 adapter.Fill(ds , "DimEmployee" );107 108 dataGridView1.DataSource = ds;109 dataGridView1.DataMember = "DimEmployee";110 111  }112 catch (Exception ex)113  {114 MessageBox.Show(ex.Message, "Fill Error", MessageBoxButtons.OK, MessageBoxIcon.Error);115  }116 finally117  {118 if (conn.State == ConnectionState.Open)119  conn.Close();120  }121  }122 123 void Count_Row()124  {125 try126  {127 conn = new SqlConnection(connectString);128  conn.Open();129 130 cmd = conn.CreateCommand();131 cmd.CommandText = "Select count(*) from DimEmployee";132 133 reader = cmd.ExecuteReader();134 if( reader.Read())135  {136 rowCount = reader.GetInt32(0);137  }138 else139  {140 MessageBox.Show("Search Error", "0 row", MessageBoxButtons.OK, MessageBoxIcon.Error);141  }142 if (reader.IsClosed)143  reader.Close();144  }145 catch (Exception ex)146  {147 MessageBox.Show(ex.Message, "Search Error", MessageBoxButtons.OK, MessageBoxIcon.Error);148  }149 finally150  {151 if (conn.State == ConnectionState.Open)152  conn.Close();153 if( reader.IsClosed)154  reader.Close();155  }156  }157  }158 }

Code3