private void Form1_Load(object sender, EventArgs e)
   {
	  this.pdfDocumentViewer1.LoadFromFile("1.pdf");
	  this.pdfDocumentViewer1.MouseDown += new MouseEventHandler(PV_Click);
	}

	private void PV_Click(object sender, MouseEventArgs e)
	{
		string outputFile = "out.Pdf";
		string outputFile_TXT = "out.txt";
		File.Delete(outputFile_TXT);           
	   if (e.Button == MouseButtons.Left) 
	   {
			PointF[] controlPositions = new PointF[] { e.Location};
			Spire.PdfViewer.Forms.PagePosition[] pagePositions = this.pdfDocumentViewer1.ControlToPage(controlPositions);                
string fileName = this.pdfDocumentViewer1.FileName;
			PdfDocument doc = new PdfDocument();
			doc.LoadFromFile(fileName,FileFormat.PDF);                
PdfPageBase page = doc.Pages[pagePositions[0].PageIndex];
		  
			RectangleF bounds = new RectangleF(pagePositions[0].Position, new SizeF(100, 100));            
			PdfTextExtractor textExtractor = new PdfTextExtractor(page);
			PdfTextExtractOptions option = new PdfTextExtractOptions();
			option.ExtractArea = bounds;
			string text = textExtractor.ExtractText(option);         
			PdfFont font = new PdfFont(PdfFontFamily.Helvetica, 11);
			PdfTextWidget pdfTextbox = new PdfTextWidget();
			pdfTextbox.Font = font;
			pdfTextbox.Brush = PdfBrushes.Red;
			pdfTextbox.Text = "stamp";                
pdfTextbox.Draw(page, bounds);                
doc.Pages[pagePositions[0].PageIndex].Canvas.DrawRectangle(PdfPens.Red, bounds);
			doc.SaveToFile(outputFile);               
File.AppendAllText(outputFile_TXT, "Position: " + pagePositions[0].Position.ToString() + "
text:\r
 " + text);                
MessageBox.Show("finish");               
doc.Dispose();
		}
	}

this.KeyPreview = true;
this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.Form1_KeyDown);
this.KeyUp += new System.Windows.Forms.KeyEventHandler(Form1_KeyUp);
this.MouseWheel += new System.Windows.Forms.MouseEventHandler(Form1_MouseWheel);

private bool m_PressCtrl = false;
private float m_ZoomFactor = 1.0f;
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
	m_PressCtrl = e.Control;
}       
private void Form1_KeyUp(object sender, KeyEventArgs e)
{
	m_PressCtrl = false;
}        
private float[] array = new float[] { 0.5f, 0.75f, 1f, 1.25f, 1.5f, 2f, 4f };
private int index = 2;     
private void Form1_MouseWheel(object sender, MouseEventArgs e)
{
	if (m_PressCtrl)
	{
		if (e.Delta > 0)
		{
			index = index < 6 ? index + 1 : 6;
		}
		if (e.Delta < 0)
		{
			index = index == 0 ? 0 : index - 1;
		}
		this.pdfViewer1.SetZoomFactor(array[index]);
	}
}

input type=button id=PdfDocumentViewer1_btnRotate onfocus=this.blur() onclick=pdfdocumentviewer1.Rotate(pdfdocumentviewer1.RotateAngle + 270); value=rotate_270 

input type=text id=PdfDocumentViewer1_txtFindText onkeydown=if(event.keyCode==13){pdfdocumentviewer1.SearchText(this.value,true);return false;} value= 

 protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                this.PdfDocumentViewer1.FindTextHighLightColor =     System.Drawing.Color.FromArgb(125, 255, 0, 0);
                this.PdfDocumentViewer1.LoadFromFile(input.pdf);
            }
        }

this.pdfDocumentThumbnail1.PageLabelColor = Color.Green;
this.pdfDocumentThumbnail1.PageLabelSelectedColor = Color.Yellow;