学习笔记：如何在各类控件中输入、输出数据。

一.textbox

TextBox 控件通常用于可编辑文本，不过也可使其成为只读控件。文本框可以显示多个行，对文本换行使其符合控件的大小以及添加基本的格式设置。TextBox 控件仅允许在其中显示或输入的文本采用一种格式。

输出：SqlConnection sqlConnection = new SqlConnection();

sqlConnection.ConnectionString =

"Server=(local);Database=EduBase2018;Integrated Security=sspi" ;

SqlCommand sqlCommand = new

SqlCommand();

sqlCommand.Connection = sqlConnection;

sqlCommand.CommandText = "SELECT * FROM Guahaodan WHERE Gh_no=@Gh_no;" ;

sqlCommand.Parameters.AddWithValue( "@Gh_no" , "5432001" );

sqlConnection.Open();

SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();

if

(sqlDataReader.Read())

{

this .Gh_no.Text = sqlDataReader[ "Gh_no" ].ToString();

this .Ghlb.Text = sqlDataReader[ "Ghlb" ].ToString();

this .Zzys.Text = sqlDataReader[ "Zzys" ].ToString();

this .Ghrxm.Text = sqlDataReader[ "Ghrxm" ].ToString();

this .Ghks.Text = sqlDataReader[ "Ghks" ].ToString();

this .Gh_date.Value = (DateTime)sqlDataReader[ "Gh_date" ];

}

sqlDataReader.Close();

输入：SqlConnection sqlConnection = newSqlConnection(); 
               
  sqlConnection.ConnectionString = 
 
  "Server=(local);Database=EduBase2018;Integrated Security=sspi" 
  ; 
 
  SqlCommand sqlCommand = sqlConnection.CreateCommand(); 
 
  sqlCommand.CommandText = 
 
  "INSERT Guahaodan (Gh_no,Ghlb,Zzys,Ghrxm,Ghks,Gh_date) VALUES(@Gh_no,@Ghlb,@Zzys,@Ghrxm,@Ghks,@Gh_date);" 
  ; 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Gh_no" 
  ,  
  this 
  .Gh_no.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Ghlb" 
  ,  
  this 
  .Ghlb.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Zzys" 
  ,  
  this 
  .Zzys.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Ghrxm" 
  ,  
  this 
  .Ghrxm.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Ghks" 
  ,  
  this 
  .Ghks.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Gh_date" 
  ,  
  this 
  .Gh_date.Value); 
 
  sqlConnection.Open(); 
 
  int  
  rowAffected = sqlCommand.ExecuteNonQuery(); 
 
  sqlConnection.Close(); 
 
  if  
  (rowAffected == 1) 
 
  { 
 
  MessageBox.Show( 
  "添加成功。" 
  ); 
 
  } 
 
  else 
 
  { 
 
  MessageBox.Show( 
  "添加失败！" 
  ); 
 
  }

二.datetimepicker

CanEnableIme 获取一个用以指示是否可以将 ImeMode 属性设置为活动值的值，以启用 IME 支持。

CanFocus 获取一个值，该值指示控件是否可以接收焦点。

CanRaiseEvents 确定是否可以在控件上引发事件。

CanSelect 获取一个值，该值指示是否可以选中控件。

Capture 获取或设置一个值，该值指示控件是否已捕获鼠标。

CausesValidation 获取或设置一个值，该值指示控件是否会引起在任何需要在接收焦点时执行验证的控件上执行验证。

Checked 获取或设置一个值，该值指示是否已用有效日期/时间值设置了 Value 属性且显示的值可以更新。

ClientRectangle 获取表示控件的工作区的矩形。

ClientSize 获取或设置控件的工作区的高度和宽度。

CompanyName 获取包含控件的应用程序的公司名称或创建者。

Container 获取 IContainer，它包含 Component。

ContainsFocus 获取一个值，该值指示控件或它的一个子控件当前是否有输入焦点。

ContextMenu 获取或设置与控件关联的快捷菜单。

ContextMenuStrip 获取或设置与此控件关联的 ContextMenuStrip。

Controls 获取包含在控件内的控件的集合。

Created 获取一个值，该值指示控件是否已经创建。

CreateParams 返回 CreateParams 用于创建此窗口。

Cursor 获取或设置当鼠标指针位于控件上时显示的光标。

CustomFormat 获取或设置自定义日期/时间格式字符串。

DataBindings 为该控件获取数据绑定。

DefaultCursor 获取或设置控件的默认光标。

DefaultImeMode 获取控件支持的输入法编辑器 (IME) 模式。

输出：SqlConnection sqlConnection = new SqlConnection();

sqlConnection.ConnectionString =

"Server=(local);Database=EduBase2018;Integrated Security=sspi" ;

SqlCommand sqlCommand = new

SqlCommand();

sqlCommand.Connection = sqlConnection;

sqlCommand.CommandText = "SELECT * FROM Guahaodan WHERE Gh_no=@Gh_no;" ;

sqlCommand.Parameters.AddWithValue( "@Gh_no" , "5432001" );

sqlConnection.Open();

SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();

if

(sqlDataReader.Read())

{

this .Gh_no.Text = sqlDataReader[ "Gh_no" ].ToString();

this .Ghlb.Text = sqlDataReader[ "Ghlb" ].ToString();

this .Zzys.Text = sqlDataReader[ "Zzys" ].ToString();

this .Ghrxm.Text = sqlDataReader[ "Ghrxm" ].ToString();

this .Ghks.Text = sqlDataReader[ "Ghks" ].ToString();

this .Gh_date.Value = (DateTime)sqlDataReader[ "Gh_date" ];

}

sqlDataReader.Close();

  输入： 
 SqlConnection sqlConnection = newSqlConnection(); 
               
  sqlConnection.ConnectionString = 
 
  "Server=(local);Database=EduBase2018;Integrated Security=sspi" 
  ; 
 
  SqlCommand sqlCommand = sqlConnection.CreateCommand(); 
 
  sqlCommand.CommandText = 
 
  "INSERT Guahaodan (Gh_no,Ghlb,Zzys,Ghrxm,Ghks,Gh_date) VALUES(@Gh_no,@Ghlb,@Zzys,@Ghrxm,@Ghks,@Gh_date);" 
  ; 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Gh_no" 
  ,  
  this 
  .Gh_no.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Ghlb" 
  ,  
  this 
  .Ghlb.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Zzys" 
  ,  
  this 
  .Zzys.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Ghrxm" 
  ,  
  this 
  .Ghrxm.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Ghks" 
  ,  
  this 
  .Ghks.Text.Trim()); 
 
  sqlCommand.Parameters.AddWithValue( 
  "@Gh_date" 
  ,  
  this 
  .Gh_date.Value); 
 
  sqlConnection.Open(); 
 
  int  
  rowAffected = sqlCommand.ExecuteNonQuery(); 
 
  sqlConnection.Close(); 
 
  if  
  (rowAffected == 1) 
 
  { 
 
  MessageBox.Show( 
  "添加成功。" 
  ); 
 
  } 
 
  else 
 
  { 
 
  MessageBox.Show( 
  "添加失败！" 
  ); 
 
  }

三.datagridview

windows系统控件名称。DataGridView 控件替换了 DataGrid 控件并添加了功能;但是也可选择保留 DataGrid 控件以备向后兼容和将来使用。有关更多信息，请参见 Windows 窗体 DataGridView 控件和 DataGrid 控件之间的区别。

输出：SqlConnection sqlConnection = new SqlConnection();

sqlConnection.ConnectionString =

"Server=(local);Database=EduBaseDemo;Integrated Security=sspi" ;

SqlCommand sqlCommand = new SqlCommand();

sqlCommand.Connection = sqlConnection;

sqlCommand.CommandText = "SELECT * FROM tb_Student;" ;

SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();

sqlDataAdapter.SelectCommand = sqlCommand;

DataTable studentTable = new

DataTable();

sqlConnection.Open();

sqlDataAdapter.Fill(studentTable);

sqlConnection.Close();

this .dgv_Score.DataSource = studentTable;

  输入： 
 SqlConnection sqlConnection = newSqlConnection();                                              
               
  sqlConnection.ConnectionString = 
 
  "Server=(local);Database=EduBaseDemo;Integrated Security=sspi" 
  ;                            
 
  SqlCommand insertCommand =  
  new  
  SqlCommand();                                                   
 
  insertCommand.Connection = sqlConnection;                                                      
 
  insertCommand.CommandText =                                                                  
 
  "INSERT tb_Student" 
 
  +  
  "(No,Name,Gender,BirthDate,Class,Speciality)" 
 
  +  
  " VALUES(@No,@Name,@Gender,@BirthDate,@Class,@Speciality);" 
  ; 
 
  insertCommand.Parameters.Add( 
  "@No" 
  , SqlDbType.Char, 10,  
  "No" 
  );                                   
  
  insertCommand.Parameters.Add( 
  "@Name" 
  , SqlDbType.VarChar, 0,  
  "Name" 
  );                                 
 
  insertCommand.Parameters.Add( 
  "@Gender" 
  , SqlDbType.VarChar, 0,  
  "Gender" 
  ); 
 
  insertCommand.Parameters.Add( 
  "@BirthDate" 
  , SqlDbType.VarChar, 0,  
  "BirthDate" 
  ); 
 
  insertCommand.Parameters.Add( 
  "@Class" 
  , SqlDbType.VarChar, 0,  
  "Class" 
  ); 
 
  insertCommand.Parameters.Add( 
  "@Speciality" 
  , SqlDbType.VarChar, 0,  
  "Speciality" 
  ); 
 
  SqlCommand updateCommand =  
  new  
  SqlCommand();                                                    
 
  updateCommand.Connection = sqlConnection;                                                       
 
  updateCommand.CommandText =                                                                      
  
  "UPDATE tb_Student" 
 
  +  
  " SET No=@NewNo,Name=@Name,Gender=@Gender,BirthDate=@BirthDate,Class=@Class,Speciality=@Speciality" 
 
  +  
  " WHERE No=@OldNo;" 
  ; 
 
  updateCommand.Parameters.Add( 
  "@NewNo" 
  , SqlDbType.Char, 10,  
  "No" 
  );                                
  
  updateCommand.Parameters.Add( 
  "@Name" 
  ,SqlDbType.VarChar,0, 
  "Name" 
  );                              
 
  updateCommand.Parameters.Add( 
  "@Gender" 
  , SqlDbType.VarChar, 0,  
  "Gender" 
  ); 
 
  updateCommand.Parameters.Add( 
  "@BirthDate" 
  , SqlDbType.VarChar, 0,  
  "BirthDate" 
  ); 
 
  updateCommand.Parameters.Add( 
  "@Class" 
  , SqlDbType.VarChar, 0,  
  "Class" 
  ); 
 
  updateCommand.Parameters.Add( 
  "@Speciality" 
  , SqlDbType.VarChar, 0,  
  "Speciality" 
  ); 
 
  updateCommand.Parameters.Add( 
  "@OldNo" 
  , SqlDbType.Char, 10,  
  "No" 
  );                               
 
  updateCommand.Parameters[ 
  "@OldNo" 
  ].SourceVersion = DataRowVersion.Original;                     
 
  SqlCommand deleteCommand =  
  new  
  SqlCommand();                                                    
 
  deleteCommand.Connection = sqlConnection;                                                       
 
  deleteCommand.CommandText =                                                                    
 
  "DELETE tb_Student" 
 
  +  
  " WHERE No=@No;" 
  ; 
 
  deleteCommand.Parameters.Add( 
  "@No" 
  , SqlDbType.Char, 10,  
  "No" 
  ); 
 
  SqlDataAdapter sqlDataAdapter =  
  new  
  SqlDataAdapter();                                           
 
  sqlDataAdapter.InsertCommand = insertCommand;                                                   
 
  sqlDataAdapter.UpdateCommand = updateCommand;                                                    
  
  sqlDataAdapter.DeleteCommand = deleteCommand;                                                    
  
  DataTable studentTable1 = (DataTable) 
  this 
  .dgv_Score.DataSource;                                  
  
  sqlConnection.Open();                                                                          
 
  int  
  rowAffected = sqlDataAdapter.Update(studentTable1);                                         
 
  sqlConnection.Close();                                                                          
 
  MessageBox.Show( 
  "更新"  
  + rowAffected.ToString() +  
  "行。" 
  );

四.combobox

1)Sort 属性:设置为 true，则新添加项将按字母顺序插入到列表中;否则，在列表的结尾处插入项。

2)Type属性:设置为Drop List，则使ComboBox不能输入只能在下拉菜单中选择;设置Dropdown,则ComboBox中允许输入内容。

3)No integral height属性，表示最大长度为设计长度，如果实际内容比设计长度多，就出现滚动条，少就以实际长度显示。

得到或设置输入框中被选中的字符位置

1)DWORD GetEditSel() /BOOL SetEditSel( int nStartChar, int nEndChar );//得到或设置输入框中被选中的字符位置。

2)BOOL LimitText(int nMaxChars );//设置输入框中可输入的最大字符数。

输出：SqlConnection sqlConnection = new SqlConnection();

sqlConnection.ConnectionString =

"Server=(local);Database=EduBaseDemo;Integrated Security=sspi" ;

SqlCommand sqlCommand = new SqlCommand();

SqlCommand sqlCommand2 = new

SqlCommand();

sqlCommand.Connection = sqlConnection;

sqlCommand2.Connection = sqlConnection;

sqlCommand.CommandText = "SELECT * FROM tb_Class;" ;

sqlCommand2.CommandText = "SELECT * FROM tb_Student WHERE No=@No;" ;

sqlCommand2.Parameters.AddWithValue( "@No" , "3120707001" );

SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();

sqlDataAdapter.SelectCommand = sqlCommand;

DataTable classTable = new DataTable();

sqlConnection.Open();

sqlDataAdapter.Fill(classTable);

this

.cmb_Class.DataSource = classTable;

this .cmb_Class.DisplayMember = "Name" ;

this .cmb_Class.ValueMember = "No"

SqlDataReader sqlDataReader = sqlCommand2.ExecuteReader();

byte [] photoBytes = null ;

if

(sqlDataReader.Read())

{

this .txb_No.Text = sqlDataReader[ "No" ].ToString();

this .txb_Name.Text = sqlDataReader[ "Name" ].ToString();

this .rdb_Male.Checked = ( bool )sqlDataReader[ "Gender" ];

this .rdb_Female.Checked = !( bool )sqlDataReader[ "Gender" ];

this .dtp_BirthDate.Value = (DateTime)sqlDataReader[ "BirthDate" ];

this .cmb_Class.SelectedValue = ( int )sqlDataReader[ "ClassNo" ];

this .txb_Speciality.Text = sqlDataReader[ "Speciality" ].ToString();

photoBytes =

(sqlDataReader[ "Photo" ] == DBNull.Value ? null : ( byte [])sqlDataReader[ "Photo" ]);

}

sqlDataReader.Close();

if (photoBytes != null

{

MemoryStream memoryStream = new MemoryStream(photoBytes);

this

.ptb_Photo.Image = Image.FromStream(memoryStream);

}

输入： OpenFileDialog openPhotoDialog = new OpenFileDialog()

Title = "打开照片文件（位图格式）"

, Filter = "BMP Files (*.bmp)|*.bmp"

, InitialDirectory = @"C:\"

};

if (openPhotoDialog.ShowDialog() == DialogResult.OK)

{

this

.PhotoFileName = openPhotoDialog.FileName;

this .ptb_Photo.Image = Image.FromFile( this .PhotoFileName);

}

五.picturebox

PictureBox 控件可以显示来自位图、图标或者元文件，以及来自增强的元文件、JPEG 或 GIF 文件的图形。如果控件不足以显示整幅图象，则裁剪图象以适应控件的大小。

输出：SqlConnection sqlConnection = new SqlConnection();

sqlConnection.ConnectionString =

"Server=(local);Database=EduBaseDemo;Integrated Security=sspi" ;

SqlCommand sqlCommand = new SqlCommand();

SqlCommand sqlCommand2 = new

SqlCommand();

sqlCommand.Connection = sqlConnection;

sqlCommand2.Connection = sqlConnection;

sqlCommand.CommandText = "SELECT * FROM tb_Class;" ;

sqlCommand2.CommandText = "SELECT * FROM tb_Student WHERE No=@No;" ;

sqlCommand2.Parameters.AddWithValue( "@No" , "3120707001" );

SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();

sqlDataAdapter.SelectCommand = sqlCommand;

DataTable classTable = new DataTable();

sqlConnection.Open();

sqlDataAdapter.Fill(classTable);

this

.cmb_Class.DataSource = classTable;

this .cmb_Class.DisplayMember = "Name" ;

this .cmb_Class.ValueMember = "No"

SqlDataReader sqlDataReader = sqlCommand2.ExecuteReader();

byte [] photoBytes = null ;

if

(sqlDataReader.Read())

{

this .txb_No.Text = sqlDataReader[ "No" ].ToString();

this .txb_Name.Text = sqlDataReader[ "Name" ].ToString();

this .rdb_Male.Checked = ( bool )sqlDataReader[ "Gender" ];

this .rdb_Female.Checked = !( bool )sqlDataReader[ "Gender" ];

this .dtp_BirthDate.Value = (DateTime)sqlDataReader[ "BirthDate" ];

this .cmb_Class.SelectedValue = ( int )sqlDataReader[ "ClassNo" ];

this .txb_Speciality.Text = sqlDataReader[ "Speciality" ].ToString();

photoBytes =

(sqlDataReader[ "Photo" ] == DBNull.Value ? null : ( byte [])sqlDataReader[ "Photo" ]);

}

sqlDataReader.Close();

if (photoBytes != null

{

MemoryStream memoryStream = new MemoryStream(photoBytes);

this

.ptb_Photo.Image = Image.FromStream(memoryStream);

}

输入： OpenFileDialog openPhotoDialog = new OpenFileDialog()

Title = "打开照片文件（位图格式）"

, Filter = "BMP Files (*.bmp)|*.bmp"

, InitialDirectory = @"C:\"

};

if (openPhotoDialog.ShowDialog() == DialogResult.OK)

{

this

.PhotoFileName = openPhotoDialog.FileName;

this .ptb_Photo.Image = Image.FromFile( this .PhotoFileName);

}

学习笔记：如何在各类控件中输入、输出数据。

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