EnumCapabilities Method

Summary

Enumerates all of the available WIA driver capabilities and properties and determines the available values for each one.

Syntax
C#
VB
C++
public void EnumCapabilities( 
   object item, 
   WiaEnumCapabilitiesFlags flags 
) 
  
Public Sub EnumCapabilities( _ 
   ByVal item As Object, _ 
   ByVal flags As WiaEnumCapabilitiesFlags _ 
)  
public: 
void EnumCapabilities(  
   Object^ item, 
   WiaEnumCapabilitiesFlags flags 
)  

Parameters

item
Handle to the item to get its capabilities. Retrieve this parameter by either calling the GetRootItem method to get the device's root item itself or by enumerating the child items of the device through a call to EnumChildItems method.

flags
Reserved for future use. Pass WiaEnumCapabilitiesFlags.None.

Remarks

This function will enumerate all of the available WIA driver capabilities and properties (and determine the available values for each one) for the specified acquisition source.

Each enumerated capability will be sent to the user through the EnumCapabilitiesEvent event. Add this event when enumerating the device's capabilities. To cancel the enumeration proces, add the EnumCapabilitiesEvent event and then set the Cancel member of the WiaEnumCapabilitiesEventArgs to true.

For more information, refer to Managing WIA Sources.

Example
C#
VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Wia; 
 
WiaSession session; 
public void EnumCapabilitiesExample(IntPtr parent) 
{ 
   if (!WiaSession.IsAvailable(WiaVersion.Version1)) 
   { 
      MessageBox.Show("WIA version 1.0 not installed."); 
      return; 
   } 
 
   session = new WiaSession(); 
   session.Startup(WiaVersion.Version1); 
 
   DialogResult res = session.SelectDeviceDlg(parent, WiaDeviceType.Default, WiaSelectSourceFlags.NoDefault); 
   if (res != DialogResult.OK) 
   { 
      MessageBox.Show("Error selecting WIA device."); 
      session.Shutdown(); 
      return; 
   } 
 
   session.EnumCapabilitiesEvent += new EventHandler<WiaEnumCapabilitiesEventArgs>(wiaSession_EnumCapabilitiesEvent); 
 
   object rootItem = session.GetRootItem(null); 
   if (rootItem != null) 
   { 
      session.EnumCapabilities(rootItem, WiaEnumCapabilitiesFlags.None); 
   } 
 
   session.EnumCapabilitiesEvent -= new EventHandler<WiaEnumCapabilitiesEventArgs>(wiaSession_EnumCapabilitiesEvent); 
 
   session.Shutdown(); 
} 
 
void wiaSession_EnumCapabilitiesEvent(object sender, WiaEnumCapabilitiesEventArgs e) 
{ 
   string strMsg = string.Empty; 
   string strPropAccess = string.Empty; 
   string strPropValue = string.Empty; 
 
   strMsg = string.Format("WIA Capabilities count = {0}\n", e.CapabilitiesCount); 
   Console.WriteLine(strMsg); 
 
   // print out the received capability information into the console window. 
   if (e.CapabilitiesCount > 0) 
   { 
      Console.WriteLine("Capability information:\n"); 
 
      // print out received capability property ID. 
      strMsg = string.Format("Property ID:\t{0}\n", e.Capability.PropertyId.ToString()); 
      Console.WriteLine(strMsg); 
 
      // print out received capability property Name. 
      strMsg = string.Format("Property Name:\t{0}\n", e.Capability.PropertyName); 
      Console.WriteLine(strMsg); 
 
      // print out received capability property access. 
      if ((e.Capability.PropertyAttributes & WiaPropertyAttributesFlags.ReadWrite) == WiaPropertyAttributesFlags.ReadWrite) 
      { 
         strPropAccess += "ReadWrite"; 
      } 
      else 
      { 
         if ((e.Capability.PropertyAttributes & WiaPropertyAttributesFlags.Read) == WiaPropertyAttributesFlags.Read) 
            strPropAccess += "Read"; 
 
         if ((e.Capability.PropertyAttributes & WiaPropertyAttributesFlags.Write) == WiaPropertyAttributesFlags.Write) 
         { 
            if (!string.IsNullOrEmpty(strPropAccess)) 
            { 
               strPropAccess += " | Write"; 
            } 
            else 
            { 
               strPropAccess += "Write"; 
            } 
         } 
      } 
 
      if ((e.Capability.PropertyAttributes & WiaPropertyAttributesFlags.Cashable) == WiaPropertyAttributesFlags.Cashable) 
      { 
         if (!string.IsNullOrEmpty(strPropAccess)) 
         { 
            strPropAccess += " | Cashable"; 
         } 
         else 
         { 
            strPropAccess += "Cashable"; 
         } 
      } 
 
      strMsg = string.Format("Property Access:\t{0}\n", strPropAccess); 
      Console.WriteLine(strMsg); 
 
      // print out received capability property value(s). 
      if ((e.Capability.PropertyAttributes & WiaPropertyAttributesFlags.List) == WiaPropertyAttributesFlags.List) 
      { 
         strPropValue = "Property List Values:\n"; 
         for (int i = 0; i < e.Capability.Values.ListValues.ValuesCount; i++) 
         { 
            if ((e.Capability.VariableType & WiaVariableTypes.Bstr) == WiaVariableTypes.Bstr) 
            { 
               strPropValue = strPropValue + "\t" + Convert.ToString(e.Capability.Values.ListValues.Values[i]) + "\n"; 
            } 
            else if ((e.Capability.VariableType & WiaVariableTypes.Clsid) == WiaVariableTypes.Clsid) 
            { 
               System.Guid guidValue = (System.Guid)e.Capability.Values.ListValues.Values[i]; 
               strPropValue = strPropValue + "\t" + guidValue.ToString() + "\n"; 
            } 
            else 
            { 
               strPropValue = strPropValue + "\t" + (Convert.ToInt32(e.Capability.Values.ListValues.Values[i])).ToString() + "\n"; 
            } 
         } 
      } 
      else if ((e.Capability.PropertyAttributes & WiaPropertyAttributesFlags.Range) == WiaPropertyAttributesFlags.Range) 
      { 
         strPropValue = string.Format("Property Range Values:\n\tMinimum Value: {0}\n\tMaximum Value: {1}\n", e.Capability.Values.RangeValues.MinimumValue, e.Capability.Values.RangeValues.MaximumValue); 
      } 
      else if ((e.Capability.PropertyAttributes & WiaPropertyAttributesFlags.Flag) == WiaPropertyAttributesFlags.Flag) 
      { 
         strPropValue = e.Capability.Values.FlagsValues.FlagValues.ToString(); 
      } 
      else  // The property value is of type "None", and in this case you can retrieve the value by calling the GetPropertyXXX method appropriate for the received variable type. 
      { 
         strPropValue = "Property Value: "; 
 
         object rootItem = session.GetRootItem(null); 
 
         if ((e.Capability.VariableType & WiaVariableTypes.Bstr) == WiaVariableTypes.Bstr) 
         { 
            string stringValue = session.GetPropertyString(rootItem, null, e.Capability.PropertyId); 
            strPropValue += stringValue; 
         } 
         else if ((e.Capability.VariableType & WiaVariableTypes.Clsid) == WiaVariableTypes.Clsid) 
         { 
            Guid guidValue = session.GetPropertyGuid(rootItem, null, e.Capability.PropertyId); 
            strPropValue += guidValue.ToString(); 
         } 
         else 
         { 
            int longValue = session.GetPropertyLong(rootItem, null, e.Capability.PropertyId); 
            strPropValue += longValue.ToString(); 
         } 
      } 
 
      Console.WriteLine(strPropValue); 
   } 
} 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Wia 
 
Dim session As WiaSession 
<TestMethod()> _ 
Public Sub EnumCapabilitiesExample(ByVal parent As IntPtr) 
   If (Not wiaSession.IsAvailable(WiaVersion.Version1)) Then 
      MessageBox.Show("WIA version 1.0 not installed.") 
      Return 
   End If 
 
   session = New WiaSession() 
   session.Startup(WiaVersion.Version1) 
 
   Dim res As DialogResult = session.SelectDeviceDlg(parent, WiaDeviceType.Default, WiaSelectSourceFlags.NoDefault) 
   If res <> DialogResult.OK Then 
      MessageBox.Show("Error selecting WIA device.") 
      session.Shutdown() 
      Return 
   End If 
 
   AddHandler session.EnumCapabilitiesEvent, AddressOf session_EnumCapabilitiesEvent 
 
   Dim rootItem As Object = session.GetRootItem(Nothing) 
   If Not rootItem Is Nothing Then 
      session.EnumCapabilities(rootItem, WiaEnumCapabilitiesFlags.None) 
   End If 
 
   RemoveHandler session.EnumCapabilitiesEvent, AddressOf session_EnumCapabilitiesEvent 
 
   session.Shutdown() 
End Sub 
 
Private Sub session_EnumCapabilitiesEvent(ByVal sender As Object, ByVal e As WiaEnumCapabilitiesEventArgs) 
   Dim strMsg As String = String.Empty 
   Dim strPropAccess As String = String.Empty 
   Dim strPropValue As String = String.Empty 
 
   strMsg = String.Format("WIA Capabilities count = {0}" & Constants.vbLf, e.CapabilitiesCount) 
   Console.WriteLine(strMsg) 
 
   ' print out the received capability information into the console window. 
   If e.CapabilitiesCount > 0 Then 
      Console.WriteLine("Capability information:" & Constants.vbLf) 
 
      ' print out received capability property ID. 
      strMsg = String.Format("Property ID:" & Constants.vbTab & "{0}" & Constants.vbLf, e.Capability.PropertyId.ToString()) 
      Console.WriteLine(strMsg) 
 
      ' print out received capability property Name. 
      strMsg = String.Format("Property Name:" & Constants.vbTab & "{0}" & Constants.vbLf, e.Capability.PropertyName) 
      Console.WriteLine(strMsg) 
 
      ' print out received capability property access. 
      If (e.Capability.PropertyAttributes And WiaPropertyAttributesFlags.ReadWrite) = WiaPropertyAttributesFlags.ReadWrite Then 
         strPropAccess &= "ReadWrite" 
      Else 
         If (e.Capability.PropertyAttributes And WiaPropertyAttributesFlags.Read) = WiaPropertyAttributesFlags.Read Then 
            strPropAccess &= "Read" 
         End If 
 
         If (e.Capability.PropertyAttributes And WiaPropertyAttributesFlags.Write) = WiaPropertyAttributesFlags.Write Then 
            If (Not String.IsNullOrEmpty(strPropAccess)) Then 
               strPropAccess &= " | Write" 
            Else 
               strPropAccess &= "Write" 
            End If 
         End If 
      End If 
 
      If (e.Capability.PropertyAttributes And WiaPropertyAttributesFlags.Cashable) = WiaPropertyAttributesFlags.Cashable Then 
         If (Not String.IsNullOrEmpty(strPropAccess)) Then 
            strPropAccess &= " | Cashable" 
         Else 
            strPropAccess &= "Cashable" 
         End If 
      End If 
 
      strMsg = String.Format("Property Access:" & Constants.vbTab & "{0}" & Constants.vbLf, strPropAccess) 
      Console.WriteLine(strMsg) 
 
      ' print out the capability property value(s) that were received. 
      If (e.Capability.PropertyAttributes And WiaPropertyAttributesFlags.List) = WiaPropertyAttributesFlags.List Then 
         strPropValue = "Property List Values:" & Constants.vbLf 
         Dim i As Integer = 0 
         Do While i < e.Capability.Values.ListValues.ValuesCount 
            If (e.Capability.VariableType And WiaVariableTypes.Bstr) = WiaVariableTypes.Bstr Then 
               strPropValue = strPropValue & Constants.vbTab + Convert.ToString(e.Capability.Values.ListValues.Values(i)) + Constants.vbLf 
            ElseIf (e.Capability.VariableType And WiaVariableTypes.Clsid) = WiaVariableTypes.Clsid Then 
               Dim guidValue As System.Guid = CType(e.Capability.Values.ListValues.Values(i), System.Guid) 
               strPropValue = strPropValue & Constants.vbTab + guidValue.ToString() + Constants.vbLf 
            Else 
               strPropValue = strPropValue & Constants.vbTab + (Convert.ToInt32(e.Capability.Values.ListValues.Values(i))).ToString() & Constants.vbLf 
            End If 
            i += 1 
         Loop 
      ElseIf (e.Capability.PropertyAttributes And WiaPropertyAttributesFlags.Range) = WiaPropertyAttributesFlags.Range Then 
         strPropValue = String.Format("Property Range Values:" & Constants.vbLf + Constants.vbTab & "Minimum Value: {0}" & Constants.vbLf + Constants.vbTab & "Maximum Value: {1}" & Constants.vbLf, 
               e.Capability.Values.RangeValues.MinimumValue, e.Capability.Values.RangeValues.MaximumValue) 
      ElseIf (e.Capability.PropertyAttributes And WiaPropertyAttributesFlags.Flag) = WiaPropertyAttributesFlags.Flag Then 
         strPropValue = e.Capability.Values.FlagsValues.FlagValues.ToString() 
      Else ' The property value is of type "None", and in this case you can retrieve the value by calling the appropriate GetPropertyXXX method according to the received variable type. 
         strPropValue = "Property Value: " 
 
         Dim rootItem As Object = session.GetRootItem(Nothing) 
 
         If (e.Capability.VariableType And WiaVariableTypes.Bstr) = WiaVariableTypes.Bstr Then 
            Dim stringValue As String = session.GetPropertyString(rootItem, Nothing, e.Capability.PropertyId) 
            strPropValue &= stringValue 
         ElseIf (e.Capability.VariableType And WiaVariableTypes.Clsid) = WiaVariableTypes.Clsid Then 
            Dim guidValue As Guid = session.GetPropertyGuid(rootItem, Nothing, e.Capability.PropertyId) 
            strPropValue &= guidValue.ToString() 
         Else 
            Dim longValue As Integer = session.GetPropertyLong(rootItem, Nothing, e.Capability.PropertyId) 
            strPropValue &= longValue.ToString() 
         End If 
      End If 
 
      Console.WriteLine(strPropValue) 
   End If 
End Sub 

Requirements

Target Platforms

Help Version 20.0.2019.9.19
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