Acquiring an Image

Take the following steps to create and run a program that acquires an image from a TWAIN source.

Start Visual Studio .NET.
Choose File->New->Project… from the menu.
In the New Project dialog box, choose either "Visual C# Projects" or "VB Projects" in the Projects Type List, and choose "Windows Application" in the Templates List.
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.
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\DotNet4\Win32" folder and select the following DLLs:
- Leadtools.dll
- Leadtools.Twain.dll
- Leadtools.Codecs.dll
- Leadtools.Controls.WinForms.dll
Click the Select button and then press the OK button to add the above DLLs to the application.
Make sure Form1 is in design view. Go to the toolbox (View->Toolbox) and Drag and drop an instance of ImageViewer to the form. If you do not have ImageViewer in your toolbox, select Tools->Choose Toolbox Items from the menu. Click Browse and then select Leadtools.Controls.WinForms.DLL from "<LEADTOOLS_INSTALLDIR>\Bin\DotNet4\Win32" and then click Open and then click OK.
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

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

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:

Imports Leadtools 
Imports Leadtools.Twain 
Imports Leadtools.Codecs 
Imports Leadtools.Controls.WinForms

using Leadtools; 
using Leadtools.Twain; 
using Leadtools.Codecs; 
using Leadtools.Controls.WinForms;

Declare the following private variable:

Private WithEvents twnSession As TwainSession

private TwainSession twnSession;

Add an event handler to the Form1 Load event and code it as follows:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
   Try 
      twnSession = new TwainSession 
      twnSession.Startup(Me.Handle, "manufacturer", "productFamily", "version", "application", TwainStartupFlags.None) 
   Catch ex As Exception 
      MessageBox.Show(ex.Message) 
   End Try 
End Sub

private void Form1_Load(object sender, System.EventArgs e) 
{ 
   try 
   { 
      twnSession = new TwainSession(); 
      twnSession.Startup(this.Handle, "manufacturer", "productFamily", "version", "application", TwainStartupFlags.None); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the Form1 Closing event and code it as follows:

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

private void Form1_FormClosing(object sender, FormClosingEventArgs e) 
{ 
   try 
   { 
      twnSession.Shutdown(); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the twnSession AcquirePage event and code it as follows:

Private Sub twnSession_AcquirePage(ByVal sender As Object, ByVal e As TwainAcquirePageEventArgs) Handles twnSession.AcquirePage 
   RasterImageViewer1.Image = e.Image 
End Sub

private void twnSession_AcquirePage(object sender, TwainAcquirePageEventArgs e) 
{ 
   rasterImageViewer1.Image = e.Image; 
}

Add an event handler to the buttonAcquire Click event and code it as follows:

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

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); 
   } 
}

Add an event handler to the buttonSelectSource Click event and code it as follows:

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

private void buttonSelectSource_Click(object sender, System.EventArgs e) 
{ 
   try 
   { 
      twnSession.SelectSource(string.Empty); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the buttonSaveTemplateFile Click event and code it as follows:

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

private void buttonSaveTemplateFile_Click(object sender, System.EventArgs e) 
{ 
   try 
   { 
      twnSession.SaveTemplateFile(@"c:\test.ltt"); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the buttonLoadTemplateFile Click event and code it as follows:

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

private void buttonLoadTemplateFile_Click(object sender, System.EventArgs e) 
{ 
   try 
   { 
      twnSession.LoadTemplateFile(@"c:\test.ltt"); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the radioNative CheckedChanged event and code it as follows:

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 = CUShort(TwainTransferMechanism.Native) 
      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set) 
   Catch ex As Exception 
      MessageBox.Show(ex.Message) 
   End Try 
End Sub

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 = (UInt16)TwainTransferMechanism.Native; 
      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the radioMemory CheckedChanged event and code it as follows:

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 = CUShort(TwainTransferMechanism.Memory) 
                       
      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set) 
   Catch ex As Exception 
      MessageBox.Show(ex.Message) 
   End Try 
End Sub

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 = (UInt16)TwainTransferMechanism.Memory; 
                       
      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the radioFile CheckedChanged event and code it as follows:

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 = CUShort(TwainTransferMechanism.File) 
                       
      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set) 
   Catch ex As Exception 
      MessageBox.Show(ex.Message) 
   End Try 
End Sub

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 = (UInt16)TwainTransferMechanism.File; 
                       
      twnSession.SetCapability(capability, TwainSetCapabilityMode.Set); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Build, and Run the program to test it.