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Acquiring an Image
ScanTutorials Take the following steps to create and run a program that acquires an image from a TWAIN source.
  1. Start Visual Studio .NET.
  2. Choose File->New->Project… from the menu.
  3. In the New Project dialog box, choose either "Visual C# Projects" or "Visual Basic Projects" in the Projects Type List, and choose "Windows Application " in the Templates List.
  4. Type the project name as " Acquiring an Image" in the Project Name field, and then choose OK. If desired, type a new location for your project or select a directory using the Browse button, and then choose OK .
  5. In the "Solution Explorer" window, right-click on the "References" folder, and select "Add Reference…" from the context menu. In the "Add Reference" dialog box, select the ".NET" tab and browse to Leadtools For .NET "<LEADTOOLS_INSTALLDIR>\Bin\DotNet\Win32 " folder and select the following DLLs:
    • Leadtools.dll
    • Leadtools.Twain.dll
    • Leadtools.Codecs.dll
    • Leadtools.WinForms.dll
    Click the Select button and then press the OK button to add the above DLLs to the application.
  6. Make sure Form1 is in design view. Go to the toolbox (View->Toolbox) and Drag and drop an instance of RasterImageViewer to the form. If you do not have RasterImageViewer in your toolbox, select Tools->Choose Toolbox Items from the menu. Click Browse and then select Leadtools.WinForms.DLL from "<LEADTOOLS_INSTALLDIR>\Bin\DotNet\Win32" and then click Open and then click OK.
  7. Go to the toolbox (View->Toolbox) and Drag and drop a 3 instance of RadioButton control to the top of the form and set the following properties for them:
    Text Name Checked
    Native radioNative False
    Memory radioMemory False
    File radioFile False
  8. Go to the toolbox (View->Toolbox) and Drag and drop a 4 instance of Button control to the top of the form and set the following properties for them:
    Text Name
    Acquire buttonAcquire
    Select Source buttonSelectSource
    Save Template File buttonSaveTemplateFile
    Load Template File buttonLoadTemplateFile
  9. Switch to Form1 code view (right-click Form1 in the solution explorer then select View Code ) and add the following lines at the beginning of the file:

    [Visual Basic]

                Imports Leadtools
                Imports Leadtools.Twain
                Imports Leadtools.Codecs
                Imports Leadtools.WinForms
                
    
    [C#]
                using Leadtools;
                using Leadtools.Twain;
                using Leadtools.Codecs;
                using Leadtools.WinForms;
                
    
  10. Declare the following private variable:

    [Visual Basic]

                Private WithEvents twnSession As TwainSession
                
    
    [C#]
                private TwainSession twnSession;
                
    
  11. Add an event handler to the Form1 Load event and code it as follows:

    [Visual Basic]

                Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
                   Try
                      twnSession = new TwainSession
                      twnSession.Startup(Me, "manufacturer", "productFamily", "version", "application", TwainStartupFlags.None)
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub
                
    
    [C#]
                private void Form1_Load(object sender, System.EventArgs e)
                {
                   try
                   {
                      twnSession = new TwainSession();
                      twnSession.Startup(this, "manufacturer", "productFamily", "version", "application", TwainStartupFlags.None);
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  12. Add an event handler to the Form1 Closing event and code it as follows:

    [Visual Basic]

                Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
                   Try
                      twnSession.Shutdown()
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub   
                
    
    [C#]
                private void Form1_FormClosing(object sender, FormClosingEventArgs e)
                {
                   try
                   {
                      twnSession.Shutdown();
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  13. Add an event handler to the twnSession AcquirePage event and code it as follows:

    [Visual Basic]

                Private Sub twnSession_AcquirePage(ByVal sender As Object, ByVal e As TwainAcquirePageEventArgs) Handles twnSession.AcquirePage
                   RasterImageViewer1.Image = e.Image
                End Sub
                
    
    [C#]
                private void twnSession_AcquirePage(object sender, TwainAcquirePageEventArgs e)
                {
                   rasterImageViewer1.Image = e.Image;
                }
                
    
  14. Add an event handler to the buttonAcquire Click event and code it as follows:

    [Visual Basic]

                Private Sub buttonAcquire_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonAcquire.Click
                   Try
                      twnSession.Acquire(TwainUserInterfaceFlags.Show)
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub   
                
    
    [C#]
                private void buttonAcquire_Click(object sender, System.EventArgs e)
                {
                   try
                   {
                      twnSession.AcquirePage += new EventHandler<TwainAcquirePageEventArgs>(twnSession_AcquirePage);
                      twnSession.Acquire(TwainUserInterfaceFlags.Show);
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  15. Add an event handler to the buttonSelectSource Click event and code it as follows:

    [Visual Basic]

                Private Sub buttonSelectSource_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonSelectSource.Click
                   Try
                      twnSession.SelectSource(String.Empty)
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub   
                
    
    [C#]
                private void buttonSelectSource_Click(object sender, System.EventArgs e)
                {
                   try
                   {
                      twnSession.SelectSource(string.Empty);
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  16. Add an event handler to the buttonSaveTemplateFile Click event and code it as follows:

    [Visual Basic]

                Private Sub buttonSaveTemplateFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonSaveTemplateFile.Click
                   Try
                      twnSession.SaveTemplateFile("c:\test.ltt")
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub
                
    
    [C#]
                private void buttonSaveTemplateFile_Click(object sender, System.EventArgs e)
                {
                   try
                   {
                      twnSession.SaveTemplateFile(@"c:\test.ltt");
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  17. Add an event handler to the buttonLoadTemplateFile Click event and code it as follows:

    [Visual Basic]

                Private Sub buttonLoadTemplateFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonLoadTemplateFile.Click
                   Try
                      twnSession.LoadTemplateFile("c:\test.ltt")
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub   
                
    
    [C#]
                private void buttonLoadTemplateFile_Click(object sender, System.EventArgs e)
                {
                   try
                   {
                      twnSession.LoadTemplateFile(@"c:\test.ltt");
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  18. Add an event handler to the radioNative CheckedChanged event and code it as follows:

    [Visual Basic]

                Private Sub radioNative_CheckedChanged(sender As System.Object, e As System.EventArgs) Handles radioNative.CheckedChanged
                   Try
                      Dim capability As New TwainCapability
                      capability.Information.ContainerType = TwainContainerType.OneValue
                      capability.Information.Type = TwainCapabilityType.ImageTransferMechanism
                
                      capability.OneValueCapability.ItemType = TwainItemType.Uint16
                      capability.OneValueCapability.Value = CType(TwainTransferMechanism.Native, Object)
                
                      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set)
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub
                
    
    [C#]
                private void radioNative_CheckedChanged(object sender, System.EventArgs e)
                {
                   try
                   {
                      TwainCapability capability = new TwainCapability();
                      capability.Information.ContainerType = TwainContainerType.OneValue;
                      capability.Information.Type = TwainCapabilityType.ImageTransferMechanism;
                
                      capability.OneValueCapability.ItemType = TwainItemType.Uint16;
                      capability.OneValueCapability.Value = TwainTransferMechanism.Native;
                
                      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set);
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  19. Add an event handler to the radioMemory CheckedChanged event and code it as follows:

    [Visual Basic]

                Private Sub radioMemory_CheckedChanged(sender As System.Object, e As System.EventArgs) Handles radioMemory.CheckedChanged
                   Try
                      Dim capability As New TwainCapability
                      capability.Information.ContainerType = TwainContainerType.OneValue
                      capability.Information.Type = TwainCapabilityType.ImageTransferMechanism
                      
                      capability.OneValueCapability.ItemType = TwainItemType.Uint16
                      capability.OneValueCapability.Value = CType(TwainTransferMechanism.Memory, Object)
                      
                      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set)
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub
                
    
    [C#]
                private void radioMemory_CheckedChanged(object sender, System.EventArgs e)
                {
                   try
                   {
                      TwainCapability capability = new TwainCapability();
                      capability.Information.ContainerType = TwainContainerType.OneValue;
                      capability.Information.Type = TwainCapabilityType.ImageTransferMechanism;
                      
                      capability.OneValueCapability.ItemType = TwainItemType.Uint16;
                      capability.OneValueCapability.Value = TwainTransferMechanism.Memory;
                      
                      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set);
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  20. Add an event handler to the radioFile CheckedChanged event and code it as follows:

    [Visual Basic]

                Private Sub radioFile_CheckedChanged(sender As System.Object, e As System.EventArgs) Handles radioFile.CheckedChanged
                   Try
                      Dim capability As New TwainCapability
                      capability.Information.ContainerType = TwainContainerType.OneValue
                      capability.Information.Type = TwainCapabilityType.ImageTransferMechanism
                      
                      capability.OneValueCapability.ItemType = TwainItemType.Uint16
                      capability.OneValueCapability.Value = CType(TwainTransferMechanism.File, Object)
                      
                      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set)
                   Catch ex As Exception
                      MessageBox.Show(ex.Message)
                   End Try
                End Sub
                
    
    [C#]
                private void radioFile_CheckedChanged(object sender, System.EventArgs e)
                {
                   try
                   {
                      TwainCapability capability = new TwainCapability();
                      capability.Information.ContainerType = TwainContainerType.OneValue;
                      capability.Information.Type = TwainCapabilityType.ImageTransferMechanism;
                      
                      capability.OneValueCapability.ItemType = TwainItemType.Uint16;
                      capability.OneValueCapability.Value = TwainTransferMechanism.File;
                      
                      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set);
                   }
                   catch (Exception ex)
                   {
                      MessageBox.Show(this, ex.Message);
                   }
                }
                
    
  21. Build, and Run the program to test it.