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vbnet MSSQL Load Images from and Save Images to a Database

請參考來源:Load Images from and Save Images to a Database
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SQLite Writing/Reading a BLOB Image into the Table

引用來源:SQLite in VB.net - Page 2
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Imports System.Data.SQLite
Imports System.IO

Public Class sqlitetutorial
   
    'Image BLOB Functions
    Private Function BlobToImage(ByVal blob)
        Dim mStream As New System.IO.MemoryStream
        Dim pData() As Byte = DirectCast(blob, Byte())
        mStream.Write(pData, 0, Convert.ToInt32(pData.Length))
        Dim bm As Bitmap = New Bitmap(mStream, False)
        mStream.Dispose()
        Return bm
    End Function

    Public Overloads Function ImageToBlob(ByVal id As String, ByVal filePath As String)
        Dim fs As FileStream = New FileStream(filePath, FileMode.Open, FileAccess.Read)
        Dim br As BinaryReader = New BinaryReader(fs)
        Dim bm() As Byte = br.ReadBytes(fs.Length)
        br.Close()
        fs.Close()
        'Create Parm
        Dim photo() As Byte = bm
        Dim SQLparm As New SQLiteParameter("@image", photo)
        SQLparm.DbType = DbType.Binary
        SQLparm.Value = photo
        Return SQLparm
    End Function

    'NOT USED IN THE SOURCE.
    Public Overloads Function ImageToBlob(ByVal id As String, ByVal image As Image)
        Dim ms As New MemoryStream()
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Png)
        'Create Parm
        Dim photo() As Byte = ms.ToArray()
        Dim SQLparm As New SQLiteParameter("@image", photo)
        SQLparm.DbType = DbType.Binary
        SQLparm.Value = photo
        Return SQLparm
    End Function

        Private Sub btn_insertimage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_insertimage.Click
        Dim f As New SaveFileDialog
        f.Filter = "SQLite 3 (*.sqlite3)|*.sqlite3|All Files|*.*"
        Dim d As New OpenFileDialog
        d.Filter = "Image (*.png)|*.png|All Files|*.*"
        If f.ShowDialog() = DialogResult.OK And d.ShowDialog() = DialogResult.OK Then
            Dim SQLconnect As New SQLite.SQLiteConnection()
            Dim SQLcommand As SQLiteCommand
            SQLconnect.ConnectionString = "Data Source=" & f.FileName & ";"
            SQLconnect.Open()
            SQLcommand = SQLconnect.CreateCommand
            'SQL query to Create Table
            SQLcommand.CommandText = "CREATE TABLE foo(id INTEGER PRIMARY KEY AUTOINCREMENT, title TEXT, description TEXT, image BLOB);"
            SQLcommand.ExecuteNonQuery()
            'Insert image, DO NOT single quote @image
            SQLcommand.CommandText = "INSERT INTO foo (image) VALUES(@image)"
            'Define @image
            SQLcommand.Parameters.Add(ImageToBlob("@image", d.FileName))
            SQLcommand.ExecuteNonQuery()
            SQLcommand.Dispose()
            SQLconnect.Close()
        End If
    End Sub

    Private Sub btn_viewimage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_viewimage.Click
        Dim f As New OpenFileDialog
        f.Filter = "SQLite 3 (*.sqlite3)|*.sqlite3|All Files|*.*"
        If f.ShowDialog() = DialogResult.OK Then
            Dim SQLconnect As New SQLite.SQLiteConnection()
            Dim SQLcommand As SQLiteCommand
            SQLconnect.ConnectionString = "Data Source=" & f.FileName & ";"
            SQLconnect.Open()
            SQLcommand = SQLconnect.CreateCommand
            SQLcommand.CommandText = "SELECT image FROM foo WHERE id = '1'"
            Dim SQLreader As SQLiteDataReader = SQLcommand.ExecuteReader()
            While SQLreader.Read()
                pic_viewimage.Image = BlobToImage(SQLreader("image"))
            End While
            SQLcommand.Dispose()
            SQLconnect.Close()
        End If
    End Sub

    Private Sub btn_updateimage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_updateimage.Click
        Dim f As New OpenFileDialog
        f.Filter = "SQLite 3 (*.sqlite3)|*.sqlite3|All Files|*.*"
        Dim d As New OpenFileDialog
        d.Filter = "Image (*.png)|*.png|All Files|*.*"
        If f.ShowDialog() = DialogResult.OK And d.ShowDialog() = DialogResult.OK Then
            Dim SQLconnect As New SQLite.SQLiteConnection()
            Dim SQLcommand As SQLiteCommand
            SQLconnect.ConnectionString = "Data Source=" & f.FileName & ";"
            SQLconnect.Open()
            SQLcommand = SQLconnect.CreateCommand
            'Update image, DO NOT single quote @image
            SQLcommand.CommandText = "UPDATE foo SET image = @image WHERE id = '1'"
            'Define @image
            SQLcommand.Parameters.Add(ImageToBlob("@image", d.FileName))
            SQLcommand.ExecuteNonQuery()
            SQLcommand.Dispose()
            SQLconnect.Close()
        End If
    End Sub
   
End Class

VB Net Graphics

program to plot 3D Function
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好利害! 專門處理 繪圖部分的區塊 ! 還有演算公式! 值得參考

取得螢幕解析度與工作區域大小

以vb.net 2005 為範例

一、取得螢幕解析度
        Dim Screen_X
        Dim Screen_Y
        Screen_X=  Screen.PrimaryScreen Screen.PrimarBounds.Width
        Screen_Y=  Screen.PrimaryScreen Screen.PrimarBounds.Height
        MessageBox.Show("螢幕解析度" & Screen_X & "X" & Screen_Y)

二、取得工作區域大小（桌面大小）
        Dim workarea_Hight As Integer
        Dim workerarea_width As Integer
        workarea_Hight = Screen.PrimaryScreen.WorkingArea.Width
        workerarea_width = Screen.PrimaryScreen.WorkingArea.Height
        MessageBox.Show("工作區域大小" & workerarea_width & "X" & workarea_Hight)

VB.Net 動態生成子控制(Button,TextBox)

引用來源:VB.Net 動態生成子控制(Button,TextBox)
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 動態生成子控制不是問題，重點是怎麼把對應的函式自動加進去。

範例一 - 動態生成 TextBox

Public Class Form
    '  動態生成 TextBox

    Private Sub Form_Shown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown

        Dim myTextBox As TextBox

        ' const declare
        Const x0 As Int32 = 20
        Const y0 As Int32 = 20
        Const w As Int32 = 100
        Const h As Int32 = 30
        Const hd As Int32 = 10
        Const cnt As Int32 = 4

        Dim i As Int32 = 0

        ' 動態生成 TextBox
        For i = 0 To cnt - 1
            myTextBox = New TextBox()
            myTextBox.Text = "button" & i
            myTextBox.Left = x0
            myTextBox.Top = y0 + i * (h + hd)
            myTextBox.Width = w
            myTextBox.Height = h
            Me.Controls.Add(myTextBox)
            AddHandler myTextBox.Click, AddressOf myTextBoxClick ' 交附給函式
        Next
    End Sub

    Private Sub myTextBoxClick(ByVal sender As Object, ByVal e As System.EventArgs)
        System.Windows.Forms.MessageBox.Show(CType(sender, TextBox).Text)
    End Sub
End Class

範例二 - 動態生成 Button (1)

初版的動態生成 Button 缺點不少，這裡是將 myButton 使用動態陣列，每個陣列名字都長得差不多，另外對應函式是用一個一個 map 起來的。原始碼如下

Public Class Form
    '  動態生成按扭
    Private myButton() As Button

    Private Sub Form_Shown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown
        ' const declare
        Const x0 As Int32 = 20
        Const y0 As Int32 = 20
        Const w As Int32 = 100
        Const h As Int32 = 30
        Const hd As Int32 = 10
        Const cnt As Int32 = 4

        Dim i As Int32 = 0
        ReDim myButton(cnt)

        ' 動態生成 button
        For i = 0 To cnt - 1
            myButton(i) = New Button()
            myButton(i).Text = "button" & i
            myButton(i).Left = x0
            myButton(i).Top = y0 + i * (h + hd)
            myButton(i).Width = w
            myButton(i).Height = h
            Me.Controls.Add(myButton(i))
        Next

        ' 進行函式對應
        AddHandler myButton(0).Click, AddressOf Func0
        AddHandler myButton(1).Click, AddressOf Func1
        AddHandler myButton(2).Click, AddressOf Func2
        AddHandler myButton(3).Click, AddressOf Func3
    End Sub

    Sub Func0()
        MsgBox("func0")
    End Sub

    Sub Func1()
        MsgBox("func1")
    End Sub

    Sub Func2()
        MsgBox("func2")
    End Sub

    Sub Func3()
        MsgBox("func3")
    End Sub
End Class

範例三 - 動態生成 Button (2)

第二版動態生成按鈕改善了一點點，由於這幾顆按鈕做的事都一樣，所以便用委派方式給同一個函式執行，但實際上效果並不彰。

Public Class Form
    '  動態生成按扭
    Private myButton() As Button

    Private Sub Form_Shown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown
        ' const declare
        Const x0 As Int32 = 20
        Const y0 As Int32 = 20
        Const w As Int32 = 100
        Const h As Int32 = 30
        Const hd As Int32 = 10
        Const cnt As Int32 = 4

        Dim i As Int32 = 0
        ReDim myButton(cnt)

        ' 動態生成 button
        For i = 0 To cnt - 1
            myButton(i) = New Button()
            myButton(i).Text = "button" & i
            myButton(i).Left = x0
            myButton(i).Top = y0 + i * (h + hd)
            myButton(i).Width = w
            myButton(i).Height = h
            Me.Controls.Add(myButton(i))
            AddHandler myButton(i).Click, AddressOf myButtonClick
        Next
    End Sub

    ' 委派函式
    Private Sub myButtonClick(ByVal sender As Object, ByVal e As System.EventArgs)
        System.Windows.Forms.MessageBox.Show(CType(sender, Button).Text)
    End Sub
End Class


範例四 - 動態生成 Button (3)

第三版動態生成按鈕改善了二個部份，我們可以借由自己寫的函式，把 Button Name 一次全換掉；除此之外，事實上 myButton 可以不用 array 方式建立，同時也可以不用宣告到全域。

注意的是那個 SetButtonName，它的引數記得是放 string，不要直接傳 Button 實體進去，傳 Button 實體進去的話，做法就要等 Button 全都建完之後才可以去呼叫 SetButtonName，效率不彰。

Public Class Form
    '  動態生成按扭


    ' 設定按鈕名稱
    Private Sub SetButtonName(ByRef btnName() as String, ByVal ParamArray Name() As String)
        For i As Int32 = 0 To UBound(btnName) - 1
            btnName(i) = Name(i)
        Next i
    End Sub

    Private Sub Form_Shown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown

        Dim btnName() As String
        ' const declare
        Const x0 As Int32 = 20
        Const y0 As Int32 = 20
        Const w As Int32 = 100
        Const h As Int32 = 30
        Const hd As Int32 = 10
        Const cnt As Int32 = 4

        Dim i As Int32 = 0
        Dim myButton As Button

        ReDim btnName(cnt)
        SetButtonName(btnName, "OK", "ERROR", "WARNNING", "RETRY")


        ' 動態生成 button
        For i = 0 To cnt - 1
            myButton = New Button()
            myButton.Text = btnName(i)
            myButton.Left = x0
            myButton.Top = y0 + i * (h + hd)
            myButton.Width = w
            myButton.Height = h
            Me.Controls.Add(myButton)
            AddHandler myButton.click, AddressOf myButtonClick
        Next
    End Sub

    Private Sub myButtonClick(ByVal sender As Object, ByVal e As System.EventArgs)
        System.Windows.Forms.MessageBox.Show(CType(sender, Button).Text)
    End Sub
End Class

總結

動態生成子控制大致上就像上述那樣，這裡提醒的是，如果每個 Button 實際上做的動態差很多，可以考慮把 myButton 宣告成陣列型態(這不是必然，不是用陣列去做時到時 mapping 會比較清楚、簡單)，接著再手動去寫一份 map，至於 Rename 部份仍可以在建立實際 Button 時進行。最後結束前，再給最後一個範例，說明建立四個 button，名稱差很多，處理的東西也差很多，寫出來會是怎樣。

Public Class Form
    '  動態生成按扭

    Private Sub SetButtonName(ByRef btnName() As String, ByVal ParamArray Name() As String)
        For i As Int32 = 0 To UBound(btnName) - 1
            btnName(i) = Name(i)
        Next i
    End Sub

    Private Sub Form_Shown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown
        Dim BtnName() As String
        ' const declare
        Const x0 As Int32 = 20
        Const y0 As Int32 = 20
        Const w As Int32 = 100
        Const h As Int32 = 30
        Const hd As Int32 = 10
        Const cnt As Int32 = 4

        Dim i As Int32 = 0
        Dim myButton As Button

        ReDim BtnName(cnt)
        SetButtonName(BtnName, "OK", "ERROR", "WARNNING", "RETRY")

        ' 動態生成 button
        For i = 0 To cnt - 1
            myButton = New Button()

            myButton.Text = BtnName(i)
            myButton.Name = "btn_" & i ' 注意，這裡視為是 button ID, 不是 button text

            myButton.Left = x0
            myButton.Top = y0 + i * (h + hd)
            myButton.Width = w
            myButton.Height = h
            Me.Controls.Add(myButton)
            AddHandler myButton.Click, AddressOf myButtonClick
        Next
    End Sub

    Dim btnIndex As Int32
    Private Sub myButtonClick(ByVal sender As Object, ByVal e As System.EventArgs)

        ' 取得是由哪個 button ID 發出來的訊息
        btnIndex = Val(CType(sender, Button).Name.Split("_")(1))

       ' 根據發出來的 button ID 做相對應的 function map，這部份比較麻煩
       Select Case btnIndex
            Case 0
                Func0()
            Case 1
                Func1()
            Case 2
                Func2()
            Case 3
                Func3()
        End Select
    End Sub


    Public Sub Func0()
        MsgBox("func0")
    End Sub


    Public Sub Func1()
        MsgBox("func1")
    End Sub

    Public Sub Func2()
        MsgBox("func2")
    End Sub

    Public Sub Func3()
        MsgBox("func3")
    End Sub

    Public Sub Func4()
        MsgBox("func4")
    End Sub
End Class

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ReactOS

ReactOS 官網(下載)
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看起來不錯! 要用 free 的~又可相容各種 windows 相關應用軟體