WinForm中自定义搜索框（水印、清空按钮、加载中图标）

public partial class CustomSearchBar : TextBox
{
private readonly Label lblwaterText = new Label(); private readonly PictureBox clearButton = new PictureBox(); private readonly int cancelImageSize = ; private int loadingCharsCount = ; public CustomSearchBar()
{
InitializeComponent(); lblwaterText.BorderStyle = BorderStyle.None;
lblwaterText.Enabled = false;
lblwaterText.BackColor = Color.White;
lblwaterText.AutoSize = false;
lblwaterText.Top = ;
lblwaterText.Left = ;
lblwaterText.FlatStyle = FlatStyle.System;
Controls.Add(lblwaterText); clearButton.Size = new Size(cancelImageSize, cancelImageSize);
//clearButton.AutoSize = false;
clearButton.SizeMode = PictureBoxSizeMode.StretchImage;
//clearButton.Image = ResourceHandler.LoadImage("Loading");
clearButton.Top = ;
clearButton.Left = this.Width - cancelImageSize - ;
clearButton.Click += new EventHandler(clearButton_Click);
Controls.Add(clearButton);
} public void AdjustClearButtonPosition(int width)
{
this.clearButton.Left = width - cancelImageSize - ;
} public string WaterText
{
get { return lblwaterText.Text; }
set { lblwaterText.Text = value; }
} public override string Text
{
set
{
lblwaterText.Visible = value == string.Empty;
base.Text = value;
}
get
{
return base.Text;
}
} protected override void OnSizeChanged(EventArgs e)
{
if (Multiline && (ScrollBars == ScrollBars.Vertical || ScrollBars == ScrollBars.Both))
lblwaterText.Width = Width - ;
else
lblwaterText.Width = Width;
lblwaterText.Height = Height - ;
base.OnSizeChanged(e);
} protected override void OnTextChanged(EventArgs e)
{
lblwaterText.Visible = base.Text == string.Empty;
base.OnTextChanged(e);
} protected override void OnMouseDown(MouseEventArgs e)
{
lblwaterText.Visible = false;
base.OnMouseDown(e);
} protected override void OnMouseLeave(EventArgs e)
{
lblwaterText.Visible = base.Text == string.Empty;
base.OnMouseLeave(e);
} /// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void clearButton_Click(object sender, EventArgs e)
{
this.Text = string.Empty;
ClearSearchingTextHandler();
} public void StartLoadSmartTip()
{
this.clearButton.Image = ResourceHandler.LoadImage("Loading");
loadingCharsCount++;
} public void EndLoadSmartTip()
{
loadingCharsCount--;
if (loadingCharsCount <= )
{
this.clearButton.Image = ResourceHandler.LoadImage("CloseButtonInactive");
}
} public delegate void ClearSearchingText();
public event ClearSearchingText ClearSearchingTextHandler;
}