Using the WebImageViewer control on the server side

Perform the following steps to create a project that uses the features of the LEADTOOLS WebImageViewer Control from the server side:

Start Visual Studio 2005.
Choose File->New->Web Site… from the menu.
In the New Web Site dialog box, choose "ASP.NET Web Site" in the Templates List, and choose either "Visual C#" or "VB" in the Language drop-down list box.
In the Location drop-down list box choose "File System". Enter “C:\Inetpub\wwwroot\UsingImageViewer_Server” into the Project Name field, and then click OK.

If desired, type a new location for your project or select a directory by clicking Browse, and then click OK.
In the Solution Explorer pane, right-click on the project node, and select "Add Reference…" from the context menu. In the Add Reference dialog box, click the .NET tab and select "System.Windows.Forms". Click OK to close the Add Reference dialog box.
Repeat the previous step but this time in the Add Reference dialog box select the Browse tab. Browse to the "<LEADTOOLS_INSTALLDIR>\Bin\Dotnet\Win32" folder and select the following DLL:
- Leadtools.Web.dll.
Now click OK to close the Add Reference dialog box.
In the Solution Explorer pane right-click on the "Default.aspx" file and choose the View Designer from the context menu.
Go to the toolbox (View->Toolbox) and drag and drop an instance of the WebImageImageViewer onto the web form. If you do not have the WebImageViewer in your toolbox, select "Tools->Choose Toolbox Items..." from the menu. Click Browse and then select "Leadtools.Web.dll" from the "<LEADTOOLS_INSTALLDIR>\Bin\Dotnet\Win32" folder and then click Open and then click OK.
Go to the toolbox (View-Toolbox) and from the Standard tab drag and drop 7 Labels, 4 Text Boxes, 4 drop-down list boxes, and 3 Buttons onto the web form.

Change the properties of the dropped controls as follows:

Control	Property	New Value
Label1	IDText	_lblImageUrlImage Url
TextBox1	ID	_tbImageUrl
Label2	IDText	_lblImageWidthImage Width
TextBox2	ID	_tbImageWidth
Label3	IDText	_lblImageHeightImage Height
TextBox3	ID	_tbImageHeight
Button1	IDText	_btnGetImageSizeGet Image Size
Button2	IDText	_btnViewImageView Image
Label4	IDText	_lblSizeModeSizeMode
DropDownList1	IDAutoPostBack	_ddlSizeModeTrue
Label5	IDText	_lblScaleFactorScaleFactor
DropDownList2	IDAutoPostBack	_ddlScaleFactorTrue
Label6	IDText	_lblHorizontalAlignModeHorizontalAlignMode
DropDownList3	IDAutoPostBack	_ddlHorizontalAlignModeTrue
Label7	IDText	_lblVerticalAlignModeVerticalAlignMode
DropDownList4	IDAutoPostBack	_ddlVerticalAlignModeTrue
Button3	IDText	_btnGetRealScaleFactorsGet Real Scale Factors
TextBox4	ID	_tbRealScaleFactors

Switch to the "Default.aspx" code view (right-click default.aspx in the Solution Explorer, then select View Code), and add the following lines at the beginning of the file:

Imports System.Windows.Forms 
Imports System.Web.Hosting 
Imports System.Xml 
Imports System.Drawing 
                 
Imports System.IO 
Imports Leadtools.Web.Controls 
Imports Leadtools.Web.Handlers

using System.Windows.Forms; 
using System.Web.Hosting; 
using System.Xml; 
using System.IO; 
using System.Drawing; 
                 
using Leadtools.Web.Controls; 
using Leadtools.Web.Handlers;

Update the Page_Load event handler to be as follows:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 
   If (Not IsPostBack) Then 
      ' Initialize the WebImageViewer control. 
      ImageViewer1.ResourcesPath = "Resources" 
      ImageViewer1.ScrollBarSize = SystemInformation.VerticalScrollBarWidth 
      ' Fill in the Combo Boxes 
      BindDropDownListToEnum(_ddlSizeMode, GetType(ImageViewerSizeMode), ImageViewer1.SizeMode) 
      BindDropDownListToEnum(_ddlHorizontalAlignMode, GetType(ImageViewerAlignMode), ImageViewer1.HorizontalAlignMode) 
      BindDropDownListToEnum(_ddlVerticalAlignMode, GetType(ImageViewerAlignMode), ImageViewer1.VerticalAlignMode) 
      Dim scaleFactors() As Integer = {1000, 800, 600, 400, 200, 100, 75, 50, 25, 10} 
      Dim factor1 As Integer = CInt(ImageViewer1.ScaleFactor) 
      For i As Integer = 0 To scaleFactors.Length - 1 
         _ddlScaleFactor.Items.Add(scaleFactors(i).ToString()) 
         If (factor1 = scaleFactors(i)) Then 
            _ddlScaleFactor.SelectedIndex = i 
         End If 
      Next 
   End If 
End Sub

protected void Page_Load(object sender, EventArgs e) 
{ 
   if(!IsPostBack) 
   { 
      // Initialize the WebImageViewer control. 
      ImageViewer1.ResourcesPath = "Resources"; 
      ImageViewer1.ScrollBarSize = SystemInformation.VerticalScrollBarWidth; 
                    
      // Fill in the Drop-down list boxes 
      BindDropDownListToEnum(_ddlSizeMode, typeof(ImageViewerSizeMode), ImageViewer1.SizeMode); 
      BindDropDownListToEnum(_ddlHorizontalAlignMode, typeof(ImageViewerAlignMode), ImageViewer1.HorizontalAlignMode); 
      BindDropDownListToEnum(_ddlVerticalAlignMode, typeof(ImageViewerAlignMode), ImageViewer1.VerticalAlignMode); 
                    
      int[] scaleFactors = { 1000, 800, 600, 400, 200, 100, 75, 50, 25, 10 }; 
      int factor1 = (int)(ImageViewer1.ScaleFactor); 
      for(int i = 0; i < scaleFactors.Length; i++) 
      { 
         _ddlScaleFactor.Items.Add(scaleFactors[i].ToString()); 
         if(factor1 == scaleFactors[i]) 
            _ddlScaleFactor.SelectedIndex = i; 
      } 
   } 
}

double-click on the _btnGetImageSize, _btnViewImage, _ddlSizeMode, _ddlScaleFactor, _ddlHorizontalAlignMode _ddlVerticalAlignMode, and _btnGetRealScaleFactors controls and update the event handlers as follows:

Protected Sub _btnGetImageSize_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles _btnGetImageSize.Click 
   Dim queryString As String = String.Format("url={0}", _tbImageUrl.Text) 
   Dim sbResponse As StringWriter = New StringWriter() 
   Dim wr As HttpWorkerRequest = New SimpleWorkerRequest("", queryString, sbResponse) 
   Dim context As HttpContext = New HttpContext(wr) 
   Dim ii As ImageInformation = New ImageInformation() 
   ii.ProcessRequest(context) 
   Dim xmlInfo As XmlDocument = New XmlDocument() 
   If (sbResponse.ToString().Length > 0) Then 
      xmlInfo.LoadXml(sbResponse.ToString()) 
      Dim width As XmlNode = xmlInfo.SelectSingleNode("descendant::Width") 
      Dim height As XmlNode = xmlInfo.SelectSingleNode("descendant::Height") 
      If (Not width Is Nothing) Then 
         _tbImageWidth.Text = width.InnerXml 
      End If 
      If (Not height Is Nothing) Then 
         _tbImageHeight.Text = height.InnerXml 
      End If 
   End If 
End Sub 
Protected Sub _btnViewImage_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles _btnViewImage.Click 
   ImageViewer1.ImageSize = New Size(Convert.ToInt32(_tbImageWidth.Text), Convert.ToInt32(_tbImageHeight.Text)) 
   ImageViewer1.ImageUrl = _tbImageUrl.Text 
End Sub 
Protected Sub _ddlSizeMode_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles _ddlSizeMode.SelectedIndexChanged 
   ImageViewer1.SizeMode = GetDropDownListSelectedItem(_ddlSizeMode, GetType(ImageViewerSizeMode)) 
End Sub 
Protected Sub _ddlScaleFactor_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles _ddlScaleFactor.SelectedIndexChanged 
   ImageViewer1.ScaleFactor = Convert.ToInt32(_ddlScaleFactor.SelectedItem.Value) 
End Sub 
Protected Sub _ddlHorizontalAlignMode_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles _ddlHorizontalAlignMode.SelectedIndexChanged 
   ImageViewer1.HorizontalAlignMode = GetDropDownListSelectedItem(_ddlHorizontalAlignMode, GetType(ImageViewerAlignMode)) 
End Sub 
Protected Sub _ddlVerticalAlignMode_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles _ddlVerticalAlignMode.SelectedIndexChanged 
   ImageViewer1.VerticalAlignMode = GetDropDownListSelectedItem(_ddlVerticalAlignMode, GetType(ImageViewerAlignMode)) 
End Sub 
Protected Sub _btnGetRealScaleFactors_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles _btnGetRealScaleFactors.Click 
   _tbRealScaleFactors.Text = String.Format("Horizontal:{0}, Vertical:{1}", ImageViewer1.HorizontalRealScaleFactor, ImageViewer1.VerticalRealScaleFactor) 
End Sub

protected void _btnGetImageSize_Click(object sender, EventArgs e) 
{ 
   string queryString = string.Format("url={0}", _tbImageUrl.Text); 
   StringWriter sbResponse = new StringWriter(); 
   HttpWorkerRequest wr = new SimpleWorkerRequest("", queryString, sbResponse); 
   HttpContext context = new HttpContext(wr); 
   ImageInformation ii = new ImageInformation(); 
   ii.ProcessRequest(context); 
   XmlDocument xmlInfo = new XmlDocument(); 
   if(sbResponse.ToString().Length > 0) 
   { 
      xmlInfo.LoadXml(sbResponse.ToString()); 
      XmlNode width = xmlInfo.SelectSingleNode("descendant::Width"); 
      XmlNode height = xmlInfo.SelectSingleNode("descendant::Height"); 
      if(width != null) 
      { 
         _tbImageWidth.Text = width.InnerXml; 
      } 
                    
      if(height != null) 
      { 
         _tbImageHeight.Text = height.InnerXml; 
       } 
   } 
} 
protected void _btnViewImage_Click(object sender, EventArgs e) 
{ 
   ImageViewer1.ImageSize = new Size(Convert.ToInt32(_tbImageWidth.Text), Convert.ToInt32(_tbImageHeight.Text)); 
   ImageViewer1.ImageUrl = _tbImageUrl.Text; 
} 
protected void _ddlSizeMode_SelectedIndexChanged(object sender, EventArgs e) 
{ 
  ImageViewer1.SizeMode = (ImageViewerSizeMode)GetDropDownListSelectedItem(_ddlSizeMode, typeof(ImageViewerSizeMode)); 
} 
protected void _ddlScaleFactor_SelectedIndexChanged(object sender, EventArgs e) 
{ 
  ImageViewer1.ScaleFactor = Convert.ToInt32(_ddlScaleFactor.SelectedItem.Value); 
} 
protected void _ddlHorizontalAlignMode_SelectedIndexChanged(object sender, EventArgs e) 
{ 
  ImageViewer1.HorizontalAlignMode = (ImageViewerAlignMode)GetDropDownListSelectedItem(_ddlHorizontalAlignMode, typeof(ImageViewerAlignMode)); 
} 
protected void _ddlVerticalAlignMode_SelectedIndexChanged(object sender, EventArgs e) 
{ 
  ImageViewer1.VerticalAlignMode = (ImageViewerAlignMode)GetDropDownListSelectedItem(_ddlVerticalAlignMode, typeof(ImageViewerAlignMode)); 
} 
                 
protected void _btnGetRealScaleFactors_Click(object sender, EventArgs e) 
{ 
   _tbRealScaleFactors.Text = string.Format("Horizontal:{0}, Vertical:{1}", ImageViewer1.HorizontalRealScaleFactor, ImageViewer1.VerticalRealScaleFactor); 
}

Add the following functions to the end of the "Default.aspx.cs" file (for C#) or before the "End Class" statement (for VB):

Private Sub BindDropDownListToEnum(ByVal ddl As DropDownList, ByVal t As Type, ByVal selected As Object) 
   Dim a As Array = [Enum].GetValues(t) 
   ddl.DataSource = a 
   ddl.DataBind() 
   Dim selectedValue As String = selected.ToString() 
   For i As Integer = 0 To ddl.Items.Count - 1 
      If (ddl.Items(i).Value = selectedValue) Then 
         ddl.SelectedIndex = i 
         Return 
      End If 
   Next 
End Sub 
Private Function GetDropDownListSelectedItem(ByVal ddl As DropDownList, ByVal t As Type) As Object 
   Return [Enum].Parse(t, ddl.SelectedItem.Value) 
End Function

private void BindDropDownListToEnum(DropDownList ddl, Type t, object selected) 
{ 
   Array a = Enum.GetValues(t); 
   ddl.DataSource = a; 
   ddl.DataBind(); 
   string selectedValue = selected.ToString(); 
   for(int i = 0; i < ddl.Items.Count; i++) 
   { 
      if(ddl.Items[i].Value == selectedValue) 
      { 
         ddl.SelectedIndex = i; 
         return; 
      } 
   } 
} 
private object GetDropDownListSelectedItem(DropDownList ddl, Type t) 
{ 
   return Enum.Parse(t, ddl.SelectedItem.Value); 
}

From the path "<LEADTOOLS_INSTALLDIR>\Bin\Dotnet\Win32", copy the Leadtools.Codecs.Bmp, Leadtools.Codecs.Gif, Leadtools.Codecs.Png and Leadtools.Codecs.Cmp DLLs to the project's Bin folder.
Inside the project folder create a folder named "Resources" and copy all of the java script files and images found in the "<LEADTOOLS_INSTALLDIR>\Examples\DotNet\Resources\Web" folder to it.
Run the project and play with it as follows:
- Type a path to one of the Internet Browser supported formats (gif, bmp, png or jpeg) in the ImageUrl TextBox.
- Click GetImageSize to update the ImageWidth and ImageHeight Text Boxes by the image width and height.
- Click ViewImage to load the image into the WebImageViewer control.
- Change the selected items in the drop-down list boxes and notice the differences in the displayed image.