伊のspace～芳香精油＊美容保養＊程式設計

說明：
1.拖曳SqlDataSource至頁面，設定好SQL語法。
2.拖曳GridView至頁面，設定來源為SqlDataSource。
3.請於GridView_PreRender加入以下程式碼。

'DataTable存成CSV檔的程式碼----------------------------------
Dim SavePath As String = "C:\Temp\"
Dim FileName As String = "Test.csv"
Dim FilePath As String = SavePath + FileName
Dim sw As New System.IO.StreamWriter(FilePath , False, System.Text.Encoding.Default)

'寫入欄位名稱
If MyDataTable.Columns.Count > 0 Then
    sw.Write(MyDataTable.Columns.Item(0).ColumnName.ToString)
End If
For i As Integer = 1 To MyDataTable.Columns.Count - 1
    sw.Write("," + MyDataTable.Columns.Item(i).ColumnName.ToString)
Next
sw.Write(sw.NewLine)

'寫入各欄位資料
For i As Integer = 0 To MyDataTable.Rows.Count - 1
    For j As Integer = 0 To MyDataTable.Columns.Count - 1
        If j = 0 Then
            sw.Write(MyDataTable.Rows(i)(j))
        Else
            sw.Write("," + MyDataTable.Rows(i)(j))
        End If
    Next
    sw.Write(sw.NewLine)
Next

sw.Close()

'使用SaveAs.aspx隱藏檔案路徑讓使用者下載
Response.Redirect("SaveAs.aspx?filename=" + FileName)

'SaveAs.aspx.vb Page_Load 內的程式碼--------------------------
Dim SavePath As String = "C:\Temp\"
Dim FileName As String = Request.QueryString("filename").ToString
Dim FilePath As String = SavePath + FileName

'設定表頭並存檔
If System.IO.File.Exists(filep) Then
    With Response
        .ContentType = "application/save-as"
        .AddHeader("content-disposition", "attachment; filename=" & FileName)
        .ContentEncoding = Encoding.UTF8
        .WriteFile(FilePath)
    End With
Else
    Response.Write("no file")
End If

'做成Class方便使用
Public Class ExportCSV
    Function DataTableToCSV(ByVal dt As Data.DataTable, ByVal FileName As String, ByVal SavePath As String) As Boolean
        Dim FilePath As String = SavePath + FileName
        Try
            Dim sw As New System.IO.StreamWriter(FilePath, False, System.Text.Encoding.Default)

            If dt.Columns.Count > 0 Then
                sw.Write(dt.Columns.Item(0).ColumnName.ToString)
            End If
            For i As Integer = 1 To dt.Columns.Count - 1
                sw.Write("," + dt.Columns.Item(i).ColumnName.ToString)
            Next
            sw.Write(sw.NewLine)

            For i As Integer = 0 To dt.Rows.Count - 1
                For j As Integer = 0 To dt.Columns.Count - 1
                    If j = 0 Then
                        sw.Write(dt.Rows(i)(j))
                    Else
                        sw.Write("," + dt.Rows(i)(j))
                    End If
                Next
                sw.Write(sw.NewLine)
            Next
            sw.Close()
        Catch ex As Exception
            'MsgBox(ex.Message)
            Throw ex
        End Try

        If System.IO.File.Exists(FilePath) Then
            Return True
        Else
            Return False
        End If

    End Function
End Class

'存成CSV檔
Dim SavePath As String = "C:\Temp\"
Dim FileName As String = "Test.csv"
Dim epCsv As New ExportCSV
If epCsv.DataTableToCSV(MyDataTable, FileName, SavePath) = True Then
    Response.Redirect("SaveAs.aspx?filename=" + FileName)
End If

程式語言命名慣例

Visual Basic：

Visual Basic命名慣例是使用：匈牙利命名法、PascalCasing、camelCasing。

匈牙利命名法：原則將名稱分為兩個部份，字首3個字母小寫為變數之型別，字尾為變數的意義以大小寫混用取名。例：Dim strUserName As String = "Allen"，Dim intAge As Integer = 20。

PascalCasing命名法：每個字的第一個字元為大寫，例如：FirstName、LastName。

本文參考yc421206-[C#.NET] 如何 使用 多執行緒 Thread / 跨執行緒 存取UI
本文參考catyku-C# Thread應用

目標：
1.使用SqlDataSource與GridView製作不用撰寫程式碼之頁面。
2.使用Ajax元件讓網頁不閃爍。
3.使用GridView元件編輯功能，並附加使用者輸入資料之驗證功能。

asp.net 的圖表元件 chart，可能會遇上「執行 ChartImg.axd 的子要求時發生錯誤」的error...

解決方法就是在web.config裡面，找到以下兩項做修改：(加上POST)

tag：httpHandlers中