C#Excel 생성, 읽기 및 수정 방법

   // Namespaces, Variables, and Constants 
  
 using System; 
  
 using System.Configuration; 
  
 using System.Data; 
  
 private OleDbDataAdapter da; 
  
 private DataTable dt; 
  
 private void Excel_Load(object sender, System.EventArgs e) 
  
 { 
  
     // Create the DataAdapter. 
  
     da = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", ConfigurationSettings.AppSettings["ExcelConnectString1"]); 
  
     // Create the insert command. 
  
     String insertSql = "INSERT INTO [Sheet1$] (CategoryID, CategoryName, Description) VALUES (?, ?, ?)"; 
  
     da.InsertCommand = new OleDbCommand(insertSql, da.SelectCommand.Connection); 
  
     da.InsertCommand.Parameters.Add("@CategoryID", OleDbType.Integer, 0, "CategoryID"); 
  
     da.InsertCommand.Parameters.Add("@CategoryName", OleDbType.Char, 15, "CategoryName"); 
  
     da.InsertCommand.Parameters.Add("@Description", OleDbType.VarChar, 100, "Description"); 
  
     // Create the update command. 
  
     String updateSql = "UPDATE [Sheet1$] SET CategoryName=?, Description=? " WHERE CategoryID=?"; 
  
     da.UpdateCommand = new OleDbCommand(updateSql, da.SelectCommand.Connection); 
  
     da.UpdateCommand.Parameters.Add("@CategoryName", OleDbType.Char, 15, "CategoryName"); 
  
     da.UpdateCommand.Parameters.Add("@Description", OleDbType.VarChar, 100, "Description"); 
  
     da.UpdateCommand.Parameters.Add("@CategoryID", OleDbType.Integer, 0, "CategoryID"); 
  
     // Fill the table from the Excel spreadsheet. 
  
     dt = new DataTable( ); 
  
     da.Fill(dt); 
  
     // Define the primary key. 
  
     dt.PrimaryKey = new DataColumn[] {dt.Columns[0]}; 
  
     // Records can only be inserted using this technique. 
  
     dt.DefaultView.AllowDelete = false; 
  
     dt.DefaultView.AllowEdit = true; 
  
     dt.DefaultView.AllowNew = true; 
  
     // Bind the default view of the table to the grid. 
  
     dataGrid.DataSource = dt.DefaultView; 
  
 } 
  
 private void updateButton_Click(object sender, System.EventArgs e) 
  
 { 
  
     da.Update(dt); 
  
 }