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 "Visual Basic 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:

[Visual Basic]


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

[C#]


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

Declare the following private variable:

[Visual Basic]


            Private WithEvents twnSession As TwainSession

[C#]


            private TwainSession twnSession;

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.Handle, "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.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:

[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);
               }
            }

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;
            }

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);
               }
            }

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);
               }
            }

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);
               }
            }

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);
               }
            }

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 = CUShort(TwainTransferMechanism.Native)
                  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 = (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:

[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 = CUShort(TwainTransferMechanism.Memory)
                  
                  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 = (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:

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

Build, and Run the program to test it.