example2.vb

asp入门到精通的源代码

Option Strict Off

Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.HTMLControls
Imports System.Data
Imports System.Data.ADO

Public Class Example : Inherits Page

   'dim variables from aspx page
   public DataGrid1 as DataGrid
   public Label1 as Label
   public tbFName as TextBox
   public tbLName as TextBox
   public tbAddress as TextBox
   public tbCity as TextBox
   public tbState as TextBox
   public tbZip as TextBox
   public tbPhone as TextBox
   public Submit as button
   public Panel1 as Panel
   
   'declare connection
   dim Conn as new ADOConnection("DSN=21DaysBanking")
   dim ds as new DataSet("MyDataSet")
         
   sub Page_Load(obj as Object, e as EventArgs) 
      if Not Page.IsPostBack then
         FillDataGrid()
      end if
   end sub
   
   sub Submit_Click(obj as object, e as eventargs)
      'insert new data
      dim i, j as integer
      dim strText as string
      dim blnGo as boolean = true
       
      j = 0
      GetData()
      
      dim dr as DataRow = ds.Tables("tblUsers").NewRow()
      for i = 0 to Panel1.Controls.Count - 1
         if Panel1.controls(i).GetType = GetType(TextBox) then
            strText = Ctype(Panel1.Controls(i), TextBox).Text
            if strText <> "" then
               dr(j) = strText
            else
               blnGo = false
               Label1.Text = Label1.Text & "You forgot to enter " & _
                  "a value for " & Panel1.Controls(i).ID & "<p>"
            end if
            j = j + 1
         end if
      next
      
      if not blnGo then
         exit sub
      end if
      
      ds.Tables("tblUsers").Rows.Add(dr)
       
      ExecuteStatement()
      
      FillDataGrid()
       
   end sub
    
    sub DataGrid1_Edit(obj as object, e as DataGridCommandEventArgs)
       FillDataGrid(e.Item.ItemIndex)
    end sub
    
   sub DataGrid1_Delete(obj as object, e as DataGridCommandEventArgs)
      GetData()
      
      ds.Tables("tblUsers").Rows(e.Item.ItemIndex).Delete
       
      ExecuteStatement()
       
      FillDataGrid()
   end sub
    
   sub DataGrid1_Update(obj as object, e as DataGridCommandEventArgs)
      if UpdateDataStore(e) then
         FillDataGrid(-1)
      else
         Label1.Text = "Failed"
      end if
   end sub
    
   sub DataGrid1_Cancel(obj as object, e as DataGridCommandEventArgs)
      FillDataGrid(-1)
   end sub
    
   sub DataGrid1_PageIndexChanged(obj as Object, e as DataGridPageChangedEventArgs)
      DataGrid1.DataBind()
   end sub
    
   private function UpdateDataStore(e as DataGridCommandEventArgs) _
      as boolean
       
      dim i,j as integer
      dim strText as string
      dim blnGo as boolean = True
      
      j = 0
      GetData()
      
      for i = 1 to e.Item.Cells.Count - 3
         strText = Ctype(e.Item.Cells(i).Controls(0), TextBox).Text
         if strText <> "" then
            ds.Tables("tblUsers").Rows(e.Item.ItemIndex)(j) = strText
            j = j + 1
         else
            blnGo = false
            Label1.Text = Label1.Text & "You forgot to enter " & _
               "a value<p>"
         end if
      next
       
      if not blnGo then
         return false
         exit function
      end if
       
      ExecuteStatement()
      
      return blnGo
       
   end function
    
   private sub GetData()
      'open connection
      dim objCmd as ADODataSetCommand = new ADODataSetCommand _
                            ("select * from tblUsers", Conn)
      'fill dataset
      objCmd.FillDataSet(ds, "tblUsers")
      
      'define primary key
      dim keys() as DataColumn = {ds.Tables("tblUsers"). _
	                                   Columns("UserID")}
      ds.Tables("tblUsers").PrimaryKey = keys

   end sub
   
   private sub FillDataGrid(Optional EditIndex as integer=-1)
      GetData()
      
      if not EditIndex.Equals(Nothing) then
         DataGrid1.EditItemIndex = EditIndex
      end if
      
      'select data view and bind to server control
      DataGrid1.DataSource = ds.Tables("tblUsers"). _
							DefaultView
      DataGrid1.DataBind()
       
   end sub
   
   private function ExecuteStatement() 
      'open connection
      dim objCmd as new ADODataSetCommand _
                ("select * from tblUsers", Conn)

      try
         'ds.AcceptChanges()
         objCmd.Update(ds, "tblUsers")
      catch ex as ADOException
         Label1.Text = "Error updating the database. Please" & _
            " make sure all values are correctly input"
      end try
       
      ds.Clear
       
   end function
    
End Class