自定义控件中ScrollBar如何控制控件滚动

[cloudwalf]

弄了一个自定义控件，主要是两个TableLayoutPanel，一个作为表头使用，一个作为列表。要求垂直滚动条滚动时表头不动（这也是为什么用两个TableLayoutPanel的原因），水平滚动时，两个TableLayoutPanel一起滚动。
为此添加了一个VScrollBar和一个HScrollBar。但是不知道如何控制两个TableLayoutPlanel。如果单纯改变控件的loacation，界面闪烁的很厉害（控件比较多）。请问有什么办法吗？最好能有实例学习一下，谢谢。

[TTOJJ]

下面的代码示例向 PictureBox 控件添加水平和垂直滚动条，并将一个 Image 加载到该控件的 DoubleClick 事件的图片框中。您可在任何时候双击该图片框并加载新图像。如果图像比控件大，则将显示滚动条，以便您可以滚动查看图像的剩余部分。该示例假定已在 Form 上创建了一个 PictureBox（其两边分别停靠有 VScrollBar 和 HScrollBar）。它还假定已添加对 System.Drawing 命名空间的引用。请确保将 HandleScroll 方法同时设置为 VScrollBar 和 HScrollBar 的 Scroll 事件处理程序委托。有关可扩展此示例的其他代码，请参见 LargeChange、SmallChange、Maximum、Minimum 或 Value 成员。您可考虑基于滚动条的父控件的属性来设置滚动条的属性。例如，您可向该示例添加一种方法，将 Maximum 值设置为等于分配给 PictureBox 的 Image 的 Height 或 Width。将 LargeChange 值设置为等于 PictureBox 的高度或宽度（减去滚动条的高度或宽度）。这可防止用户滚动出图像的边缘，并且 LargeChange 值将只使图像的可查看区域移动与图片框中的显示区域相同的距离。



using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;


namespace Scrollbar
{
public class Form1 : Form
{
private OpenFileDialog openFileDialog1;
private PictureBox pictureBox1;
private VScrollBar vScrollBar1;
private HScrollBar hScrollBar1;

public Form1()
{
InitializeComponent();
}

private void InitializeComponent()
{
this.openFileDialog1 = new OpenFileDialog();
this.pictureBox1 = new PictureBox();
this.vScrollBar1 = new VScrollBar();
this.hScrollBar1 = new HScrollBar();
this.pictureBox1.SuspendLayout();
this.SuspendLayout();

this.pictureBox1.BorderStyle = BorderStyle.FixedSingle;
this.pictureBox1.Controls.AddRange(
new Control[] { this.vScrollBar1, this.hScrollBar1});
this.pictureBox1.Dock = DockStyle.Fill;
this.pictureBox1.Size = new System.Drawing.Size(440, 349);
this.pictureBox1.DoubleClick += new EventHandler(this.pictureBox1_DoubleClick);

this.vScrollBar1.Dock = DockStyle.Right;
this.vScrollBar1.Location = new System.Drawing.Point(422, 0);
this.vScrollBar1.Size = new System.Drawing.Size(16, 331);
this.vScrollBar1.Visible = false;
this.vScrollBar1.Scroll +=
new ScrollEventHandler(this.HandleScroll);

this.hScrollBar1.Dock = DockStyle.Bottom;
this.hScrollBar1.Location = new System.Drawing.Point(0, 331);
this.hScrollBar1.Size = new System.Drawing.Size(438, 16);
this.hScrollBar1.Visible = false;
this.hScrollBar1.Scroll +=
new ScrollEventHandler(this.HandleScroll);

this.ClientSize = new System.Drawing.Size(440, 349);
this.Controls.AddRange(new Control[] {this.pictureBox1});
this.Text = "Form1";
this.Resize += new System.EventHandler(this.Form1_Resize);
this.pictureBox1.ResumeLayout(false);
this.ResumeLayout(false);

}

[STAThread]
static void Main()
{
Application.Run(new Form1());
}

private void pictureBox1_DoubleClick (Object sender, EventArgs e)
{
// Open the dialog box so the user can select a new image.
if(openFileDialog1.ShowDialog() != DialogResult.Cancel)
{
// Display the image in the PictureBox.
pictureBox1.Image = Image.FromFile(openFileDialog1.FileName);
this.DisplayScrollBars();
this.SetScrollBarValues();
}
}

private void Form1_Resize (Object sender, EventArgs e)
{
// If the PictureBox has an image, see if it needs
// scrollbars and refresh the image.
if(pictureBox1.Image != null)
{
this.DisplayScrollBars();
this.SetScrollBarValues();
this.Refresh();
}
}

public void DisplayScrollBars()
{
// If the image is wider than the PictureBox, show the HScrollBar.
if (pictureBox1.Width > pictureBox1.Image.Width - this.vScrollBar1.Width)
{
hScrollBar1.Visible = false;
}
else
{
hScrollBar1.Visible = true;
}

// If the image is taller than the PictureBox, show the VScrollBar.
if (pictureBox1.Height >
pictureBox1.Image.Height - this.hScrollBar1.Height)
{
vScrollBar1.Visible = false;
}
else
{
vScrollBar1.Visible = true;
}
}

private void HandleScroll(Object sender, ScrollEventArgs se)
{
/* Create a graphics object and draw a portion
of the image in the PictureBox. */
Graphics g = pictureBox1.CreateGraphics();

g.DrawImage(pictureBox1.Image,
new Rectangle(0, 0, pictureBox1.Right - vScrollBar1.Width,
pictureBox1.Bottom - hScrollBar1.Height),
new Rectangle(hScrollBar1.Value, vScrollBar1.Value,
pictureBox1.Right - vScrollBar1.Width,
pictureBox1.Bottom - hScrollBar1.Height),
GraphicsUnit.Pixel);

pictureBox1.Update();
}

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;
}

}
}

[TTOJJ]

MSDN里也是重画~~你改变loaction的思路是对的~~在VC里VScrollBar从来就是一个单独的控件,(例如:没有现成的richtextbox可以用),都是靠代码来实现的

c#最不好的地方在于它让人们忘记了程序的根本!!让人以为所有的程序原本就是拖控件拖出来的

[zw880322]

帮顶。。

[cloudwalf]

二楼的，我发帖之前也GOOGLE过，搜到的都是这个例子，但是我的控件不是自绘的，所以还是不太一样。我想是不是改变LOCATION也会导致控件重绘，所以闪烁的很厉害。

顺便说一下TableLayoutPanel自带的滚动条滚动时，内容也无法同步滚动。这个是为什么呢？

[IMUSTWorking]

幫頂，學習。

[wartim]

this.SuspendLayout(); // 动前挂起布局
...
this.ResumeLayout(true); 动完恢复布局

[cloudwalf]

楼上的这个办法也用过了，没有用。
后来经一位高人指点终于解决了这个问题，拿出来跟大家分享一下。这个办法一下解决了闪烁和同步滚动两个问题。其实过程挺简单的，原因不知道谁能解释一下。

将要作为内容显示的TableLayOutPanel放入一个Panel，然后VScrollbar也放入这个Panel。然后Panel设为FILL，而TableLayOutPanel不能设为FIll（一旦Fill了肯定闪烁）。然后用VScrollbar操作TableLayOutPanel的滚动，就是LOCATION就能解决这两个问题。

其实关键是TableLayOutPanel不能设为FILL，跟那个Panel没什么关系，这就需要我们根据内容计算出TableLayOutPanel的高度，并且还要考虑窗口最大化后TableLayOutPanel自动适应的问题。

[cloudwalf]

没人回就只好结贴了