可定制的 WinForms 进度条控件 VB.NET

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引言

当前的 WinForms 进度条控件不包含任何可定制的选项或属性，并且无法继承该控件，因此我们必须自己编写代码。

我参考的 MSDN 示例是 https://support.microsoft.com/en-us/kb/323088。

上面的示例使用了用户控件，但我希望使用类控件，如果您决定使用，当然可以在您的项目中创建用户控件。

我想要一个可以自定义但仍然是进度条的进度条控件，而不是通常不用于应用程序（至少在专业情况下）的随机形状和样式。

Using the Code

该控件是使用 .NET Framework 4.0 创建的。

好的，开始吧。启动一个新的 Visual Studio 项目，并选择“类库”，然后适当地命名它。

现在在解决方案资源管理器中，右键单击项目名称并选择“添加引用”，然后从“.NET”选项卡中，添加以下内容

• 系统
• System.Drawing
• System.Windows.Forms

现在让我们导入并开始编码。添加以下内容

Imports System
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms

Public Class Progress_bar : Inherits Control

'#Region "Variables"    ' UnComment the '#Region lines to make the code collapsible

    Private min As Integer = 0
    Private max As Integer = 100
    Private val As Integer = 0
    Public usegrad As Boolean = False
    Public bkColor As Color = Color.Transparent
    Public enBackColor As Boolean = False
    Public BarColor As Color = Color.Blue
    Public gradcolor1 As Color = Color.DeepSkyBlue
    Public gradcolor2 As Color = Color.Blue
    Dim HColor As Color = Color.WhiteSmoke
    Dim hStyle As HatchStyle
    Dim drawhBrush As Boolean = False
    Dim hatchBackColor As Color = Color.Transparent '?
    Public drwLabel As Boolean = False
    Public draw3D As Boolean = False

'#End Region

'#Region "New/Create Control"

    Public Sub New()
        MyBase.New()
        SetStyle(ControlStyles.SupportsTransparentBackColor, True)
    End Sub

    Protected Overrides Sub OnCreateControl()
        MyBase.OnCreateControl()
    End Sub

'#End Region

'#Region"Properties"

    Public Property Minimum() As Integer
        Get
            Return min
        End Get
        Set(ByVal Value As Integer)
            '
            If (Value < 0) Then
                min = 0
            End If
            '
            If (Value > max) Then
                min = Value
                min = Value
            End If
            '
            If (Value < min) Then
                val = min
            End If
            '
            Me.Invalidate()
            '
        End Set
    End Property

    Public Property Maximum() As Integer
        Get
            Return max
        End Get
        Set(ByVal Value As Integer)

            If (Value < min) Then
                min = Value
            End If

            max = Value

            If (val > max) Then
                val = max
            End If

            Me.Invalidate()

        End Set
    End Property

    Public Property Value As Integer
        '
        Get
            Return val
        End Get
        '
        Set(ByVal Value As Integer)
            Dim oldvalue As Integer = val
            '
            If (Value < min) Then
                val = min
            ElseIf (Value > max) Then
                val = max
            Else
                val = Value
            End If
            '
            Dim newValueRect As Rectangle = Me.ClientRectangle
            Dim oldValueRect As Rectangle = Me.ClientRectangle
            Dim percent As Decimal
            '
            percent = (val - min) / (max - min)
            newValueRect.Width = newValueRect.Width * percent
            '
            percent = (oldvalue - min) / (max - min)
            oldValueRect.Width = oldValueRect.Width * percent
            '
            Dim updateRect As Rectangle = New Rectangle()
            '
            If (newValueRect.Width > oldValueRect.Width) Then
                updateRect.X = oldValueRect.Size.Width
                updateRect.Width = newValueRect.Width - oldValueRect.Width
            Else
                updateRect.X = newValueRect.Size.Width
                updateRect.Width = oldValueRect.Width - newValueRect.Width
            End If
            '
            updateRect.Height = Me.Height
            '
            Me.Invalidate(updateRect.X)
        End Set
        '
    End Property

    Public Property ProgressBarColor() As Color
        Get
            Return BarColor
        End Get
        Set(ByVal Value As Color)
            BarColor = Value
            Me.Invalidate()
        End Set
    End Property

    Public Property GradientColor1() As Color
        Get
            Return gradcolor1
        End Get
        Set(ByVal value As Color)
            gradcolor1 = value
            Me.Invalidate()
        End Set
    End Property

    Public Property GradientColor2() As Color
        Get
            Return gradcolor2
        End Get
        Set(ByVal value As Color)
            gradcolor2 = value
            Me.Invalidate()
        End Set
    End Property

    Public Property UseHatchBrush() As Boolean
        Get
            Return drawhBrush
        End Get
        Set(ByVal value As Boolean)
            drawhBrush = value
            Me.Invalidate()
        End Set
    End Property

    Public Property HatchColor() As Color
        Get
            Return HColor
        End Get
        Set(ByVal value As Color)

            HColor = value
            Me.Invalidate()
        End Set
    End Property

    Public Property HatchStyle() As HatchStyle
        Get
            Return hStyle
        End Get
        Set(ByVal value As HatchStyle)
            hStyle = value
            Me.Invalidate()
        End Set
    End Property

    Public Property UseGradient() As Boolean
        Get
            Return usegrad
        End Get
        Set(ByVal value As Boolean)
            usegrad = value
            Me.Invalidate()
        End Set
    End Property

    Public Property DrawLabel() As Boolean
        Get
            Return drwLabel
        End Get
        Set(ByVal value As Boolean)
            drwLabel = value
            Me.Invalidate()
        End Set
    End Property

    Public Property Draw3DBorder() As Boolean
        Get
            Return draw3D
        End Get
        Set(ByVal value As Boolean)
            draw3D = value
            Me.Invalidate()
        End Set
    End Property

    Public Shadows Property BackColor() As Color
        Get
            Return MyBase.BackColor
        End Get
        Set(ByVal value As Color)
            MyBase.BackColor = value
            Me.Invalidate()
        End Set
    End Property

'#End Region

    Private Sub Draw_3D_Border(ByVal g As Graphics)
        '
        Dim penWidth As Integer = Pens.White.Width
        g.DrawLine(Pens.DarkGray, New Point(Me.ClientRectangle.Left, _
        Me.ClientRectangle.Top), New Point(Me.ClientRectangle.Width - _
        penWidth, Me.ClientRectangle.Top))
        g.DrawLine(Pens.DarkGray, New Point(Me.ClientRectangle.Left, _
        Me.ClientRectangle.Top), New Point(Me.ClientRectangle.Left, _
        Me.ClientRectangle.Height - penWidth))
        g.DrawLine(Pens.White, New Point(Me.ClientRectangle.Left, _
        Me.ClientRectangle.Height - penWidth), New Point(Me.ClientRectangle.Width - _
        penWidth, Me.ClientRectangle.Height - penWidth))
        g.DrawLine(Pens.White, New Point(Me.ClientRectangle.Width -_ 
        penWidth, Me.ClientRectangle.Top), New Point(Me.ClientRectangle.Width - _
        penWidth, Me.ClientRectangle.Height - penWidth))
        '
    End Sub

    Protected Overrides Sub OnResize(ByVal e As EventArgs)
        Me.Invalidate()     'Invalidate to resize control
    End Sub

    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
        MyBase.OnPaint(e)
        '
        Dim g As Graphics = e.Graphics
        Dim brush As SolidBrush = New SolidBrush(BarColor) ' new solid brush from BarColor
        Dim bkbrush As New SolidBrush(MyBase.BackColor)    ' new solidbrush from backcolor
        Dim hbrush As New HatchBrush(hStyle, _
        HColor, Color.Transparent) ' new hatch brush (forecolor, backcolor)
        'new lineargradient brush
        Dim gbrush As LinearGradientBrush = New LinearGradientBrush_
        (Me.ClientRectangle, Color.FromArgb(255, gradcolor1), _
        Color.FromArgb(255, gradcolor2), LinearGradientMode.Vertical)
        Dim percent As Decimal = (val - min) / (max - min) ' calculate the percent
        Dim cliRect As Rectangle = New Rectangle(0, 0, _
        Me.ClientRectangle.Width, Me.ClientRectangle.Height) ' Control rectangle
        Dim rect As Rectangle = New Rectangle(1, 1, _
        Me.ClientRectangle.Width - 2, Me.ClientRectangle.Height - 2) ' Progress rectangle
        '
        rect.Width = rect.Width * percent
        '
        ' Smoothing and quality mode
        g.SmoothingMode = SmoothingMode.AntiAlias
        g.CompositingQuality = CompositingQuality.AssumeLinear
        '
        If UseGradient = True Then
            g.FillRectangle(bkbrush, cliRect) ' enable back color
            g.FillRectangle(gbrush, rect)     ' Use Gradient
            If drawhBrush = True Then
                g.FillRectangle(hbrush, rect) ' draw hatch brush
            End If

        End If
        '
        If UseGradient = False Then
            g.FillRectangle(bkbrush, cliRect)
            g.FillRectangle(brush, rect)
            If drawhBrush = True Then
                g.FillRectangle(hbrush, rect)
            End If
            ' g.DrawRectangle(Pens.Black, cliRect)  ' Draw a single Border
        End If
        '
        If draw3D = True Then
            Draw_3D_Border(g) ' draw the 3d border using g as graphics
        End If
        '
        If DrawLabel = True Then
            Dim str As String = CType(val & "%", String) ' convert val into a string
            Dim mybrush As New SolidBrush(Me.ForeColor)  ' make ForeColor as brush
            g.DrawString(str, Me.Font, mybrush, _
            New Point((Me.ClientRectangle.Width / 2) - str.Length * 4, _
            (Me.ClientRectangle.Height / 2) - (FontHeight / 2))) ' Draw string 
        End If
        '
        brush.Dispose()
        bkbrush.Dispose()
        hbrush.Dispose()
        gbrush.Dispose()
        g.Dispose()
        '
    End Sub

End Class

可以实现的一些样式如下所示

待办事项

• 圆角（我拥有的代码无法正常工作）
• 可选择区域
• 动画描线画笔