ScrollBar.LargeChange 属性

项目
08/17/2007

获取或设置一个值，当滚动框长距离移动时向 Value 属性加上该值或从中减去该值。

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Public Property LargeChange As Integer
用法
Dim instance As ScrollBar
Dim value As Integer

value = instance.LargeChange

instance.LargeChange = value

public int LargeChange { get; set; }

public:
property int LargeChange {
    int get ();
    void set (int value);
}

/** @property */
public int get_LargeChange ()

/** @property */
public void set_LargeChange (int value)

public function get LargeChange () : int

public function set LargeChange (value : int)

属性值

一个数值。默认值为 10。

异常

异常类型	条件
ArgumentOutOfRangeException	所分配的值小于 0。

备注

当用户按下 Page Up 或 Page Down 键或单击滚动框两侧的滚动条轨道时，Value 属性将根据 LargeChange 属性中所设置的值进行更改。

可以考虑将 LargeChange 值设置为 Height 值的百分之若干（对于垂直方向的滚动条），或者设置为 Width 值的百分之若干（对于水平方向的滚动条）。这将保持滚动条移动的距离与其大小成比例。

示例

下面的代码示例使用派生类 VScrollBar 和 HScrollBar，并设置它们的一些公共属性。它们的 Maximum 属性设置为等于分配给其父级 (PictureBox) 的 Image 的 Height 或 Width 属性值。LargeChange 属性设置为等于图片框的大小（减去滚动条的高度或宽度）。SmallChange 属性设置为等于 LargeChange 属性值除以 5。最后，两个滚动条的 Value 属性值被设置为 0。结果为在某个图片框上所显示的水平和垂直滚动条，该图片框显示 Image 的左上角。滚动条的滚动将不会超过图像的末端，并且当 LargeChange 滚动发生时，图像移动的距离仅等于在图片框中显示的区域。滚动 LargeChange 一次所移动的距离相当于滚动 SmallChange 五次所移动的距离。此代码假定已经在 Form 上创建了一个 PictureBox、一个 HScrollBar、一个 VScrollBar 和一个 Image。它还假定已添加对 System.Drawing 命名空间的引用。有关可扩展此示例的其他代码，请参见 ScrollBar 类概述。

Public Sub SetScrollBarValues()
   ' Set the Maximum, Minimum, LargeChange and SmallChange properties.
   Me.vScrollBar1.Minimum = 0
   Me.hScrollBar1.Minimum = 0
   
   ' If the offset does not make the Maximum less than zero, set its value.
   If Me.pictureBox1.Image.Size.Width - pictureBox1.ClientSize.Width > 0 Then
      Me.hScrollBar1.Maximum = Me.pictureBox1.Image.Size.Width - _
        pictureBox1.ClientSize.Width
   End If
   ' If the VScrollBar is visible, adjust the Maximum of the 
   ' HSCrollBar to account for the width of the VScrollBar.
   If Me.vScrollBar1.Visible Then
      Me.hScrollBar1.Maximum += Me.vScrollBar1.Width
   End If
   Me.hScrollBar1.LargeChange = Me.hScrollBar1.Maximum / 10
   Me.hScrollBar1.SmallChange = Me.hScrollBar1.Maximum / 20
   ' Adjust the Maximum value to make the raw Maximum value attainable by user interaction.
   Me.hScrollBar1.Maximum += Me.hScrollBar1.LargeChange
         
   ' If the offset does not make the Maximum less than zero, set its value.
   If Me.pictureBox1.Image.Size.Height - pictureBox1.ClientSize.Height > 0 Then
      Me.vScrollBar1.Maximum = Me.pictureBox1.Image.Size.Height - _
        pictureBox1.ClientSize.Height
   End If
   ' If the HScrollBar is visible, adjust the Maximum of the 
   ' VSCrollBar to account for the width of the HScrollBar.
   If Me.hScrollBar1.Visible Then
      Me.vScrollBar1.Maximum += Me.hScrollBar1.Height
   End If
   Me.vScrollBar1.LargeChange = Me.vScrollBar1.Maximum / 10
   Me.vScrollBar1.SmallChange = Me.vScrollBar1.Maximum / 20
   ' Adjust the Maximum value to make the raw Maximum value attainable by user interaction.
   Me.vScrollBar1.Maximum += Me.vScrollBar1.LargeChange
End Sub

public void SetScrollBarValues() 
{
   // Set the Maximum, Minimum, LargeChange and SmallChange properties.
   this.vScrollBar1.Minimum = 0;
   this.hScrollBar1.Minimum = 0;
   // If the offset does not make the Maximum less than zero, set its value. 
   if( (this.pictureBox1.Image.Size.Width - pictureBox1.ClientSize.Width) > 0)
   {
      this.hScrollBar1.Maximum = this.pictureBox1.Image.Size.Width - pictureBox1.ClientSize.Width;
   }
   /* If the VScrollBar is visible, adjust the Maximum of the 
      HSCrollBar to account for the width of the VScrollBar. */
   if(this.vScrollBar1.Visible)
   {
      this.hScrollBar1.Maximum += this.vScrollBar1.Width;
   }
   this.hScrollBar1.LargeChange = this.hScrollBar1.Maximum / 10;
   this.hScrollBar1.SmallChange = this.hScrollBar1.Maximum / 20;
   // Adjust the Maximum value to make the raw Maximum value attainable by user interaction.
   this.hScrollBar1.Maximum += this.hScrollBar1.LargeChange;
     
   // If the offset does not make the Maximum less than zero, set its value.    
   if( (this.pictureBox1.Image.Size.Height - pictureBox1.ClientSize.Height) > 0)
   {
      this.vScrollBar1.Maximum = this.pictureBox1.Image.Size.Height - pictureBox1.ClientSize.Height;
   }
   /* If the HScrollBar is visible, adjust the Maximum of the 
      VSCrollBar to account for the width of the HScrollBar.*/
   if(this.hScrollBar1.Visible)
   {
      this.vScrollBar1.Maximum += this.hScrollBar1.Height;
   }
   this.vScrollBar1.LargeChange = this.vScrollBar1.Maximum / 10;
   this.vScrollBar1.SmallChange = this.vScrollBar1.Maximum / 20;
   // Adjust the Maximum value to make the raw Maximum value attainable by user interaction.
   this.vScrollBar1.Maximum += this.vScrollBar1.LargeChange;
}

void SetScrollBarValues()
{
   // Set the Maximum, Minimum, LargeChange and SmallChange properties.
   this->vScrollBar1->Minimum = 0;
   this->hScrollBar1->Minimum = 0;

   // If the offset does not make the Maximum less than zero, set its value. 
   if ( (this->pictureBox1->Image->Size.Width - pictureBox1->ClientSize.Width) > 0 )
   {
      this->hScrollBar1->Maximum = this->pictureBox1->Image->Size.Width - pictureBox1->ClientSize.Width;
   }

   /* If the VScrollBar is visible, adjust the Maximum of the 
         HSCrollBar to account for the width of the VScrollBar. */
   if ( this->vScrollBar1->Visible )
   {
      this->hScrollBar1->Maximum += this->vScrollBar1->Width;
   }

   this->hScrollBar1->LargeChange = this->hScrollBar1->Maximum / 10;
   this->hScrollBar1->SmallChange = this->hScrollBar1->Maximum / 20;

   // Adjust the Maximum value to make the raw Maximum value attainable by user interaction.
   this->hScrollBar1->Maximum += this->hScrollBar1->LargeChange;

   // If the offset does not make the Maximum less than zero, set its value.    
   if ( (this->pictureBox1->Image->Size.Height - pictureBox1->ClientSize.Height) > 0 )
   {
      this->vScrollBar1->Maximum = this->pictureBox1->Image->Size.Height - pictureBox1->ClientSize.Height;
   }

   /* If the HScrollBar is visible, adjust the Maximum of the 
         VSCrollBar to account for the width of the HScrollBar.*/
   if ( this->hScrollBar1->Visible )
   {
      this->vScrollBar1->Maximum += this->hScrollBar1->Height;
   }

   this->vScrollBar1->LargeChange = this->vScrollBar1->Maximum / 10;
   this->vScrollBar1->SmallChange = this->vScrollBar1->Maximum / 20;
   
   // Adjust the Maximum value to make the raw Maximum value attainable by user interaction.
   this->vScrollBar1->Maximum += this->vScrollBar1->LargeChange;
}

public void SetScrollBarValues()
{
    // Set the Maximum, Minimum, LargeChange and SmallChange properties.
    this.vScrollBar1.set_Minimum(0);
    this.hScrollBar1.set_Minimum(0);

    // If the offset does not make the Maximum less than zero, 
    // set its value. 
    if (this.pictureBox1.get_Image().get_Size().get_Width() 
        - pictureBox1.get_ClientSize().get_Width() > 0) {
            this.hScrollBar1.set_Maximum(
                this.pictureBox1.get_Image().get_Size().get_Width() 
                - pictureBox1.get_ClientSize().get_Width());
    }

    /* If the VScrollBar is visible, adjust the Maximum of the 
       HSCrollBar to account for the width of the VScrollBar. 
     */
    if (this.vScrollBar1.get_Visible()) {
        this.hScrollBar1.set_Maximum(
            this.hScrollBar1.get_Maximum() + this.vScrollBar1.get_Width());
    }

    this.hScrollBar1.set_LargeChange(this.hScrollBar1.get_Maximum() / 10);
    this.hScrollBar1.set_SmallChange(this.hScrollBar1.get_Maximum() / 20);

    // Adjust the Maximum value to make the raw Maximum value attainable 
    // by user interaction.
    this.hScrollBar1.set_Maximum(
        this.hScrollBar1.get_Maximum() 
        + this.hScrollBar1.get_LargeChange());

    // If the offset does not make the Maximum less than zero, 
    // set its value.    
    if (this.pictureBox1.get_Image().get_Size().get_Height() 
        - pictureBox1.get_ClientSize().get_Height() > 0) {
            this.vScrollBar1.set_Maximum(
                this.pictureBox1.get_Image().get_Size().get_Height() 
                - pictureBox1.get_ClientSize().get_Height());
    }

    /* If the HScrollBar is visible, adjust the Maximum of the 
       VSCrollBar to account for the width of the HScrollBar.
     */
    if (this.hScrollBar1.get_Visible()) {
        this.vScrollBar1.set_Maximum(this.vScrollBar1.get_Maximum() 
            + this.hScrollBar1.get_Height());
    }

    this.vScrollBar1.set_LargeChange(this.vScrollBar1.get_Maximum() / 10);
    this.vScrollBar1.set_SmallChange(this.vScrollBar1.get_Maximum() / 20);

    // Adjust the Maximum value to make the raw Maximum value attainable 
    // by user interaction.
    this.vScrollBar1.set_Maximum(
        this.vScrollBar1.get_Maximum() 
        + this.vScrollBar1.get_LargeChange());
} //SetScrollBarValues

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

ScrollBar.LargeChange 属性

语法

属性值

异常

备注

示例

平台

版本信息

.NET Framework

.NET Compact Framework

请参见

参考

其他资源