C#

You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application.
You write the following code fragment.
<StackPanel TextBox.PreviewTextInput="StackPanel_PreviewTextInput">
<TextBox Name="TxtBoxA"/>
<TextBox Name="TxtBoxB"/>
<TextBox Name="TxtBoxC"/>
</StackPanel>
You create an event handler named StackPanel_PreviewTextInput. You also have a collection of strings named Keywords.
You need to ensure that TxtBoxA and TxtBoxB do not contain any of the strings in the Keywords collections.
Which code segment should you use?

A. private void StackPanel_PreviewTextInput(
object sender, TextCompositionEventArgs e)
{ FrameworkElement feSource = sender as FrameworkElement;
if (feSource.Name == "TxtBoxA" || feSource.Name == "TxtBoxB")
{ foreach(string keyword in Keywords)
{
if(e.Text.Contains(keyword)) { e.Handled = false;
return;
}
}} e.Handled = true;
} }

B. private void StackPanel_PreviewTextInput(
object sender, TextCompositionEventArgs e) {
FrameworkElement feSource = e.Source as FrameworkElement;
f (feSource.Name == "TxtBoxA" || feSource.Name == "TxtBoxB")
f (feSource.Name == "TxtBoxA" || feSource.Name == "TxtBoxB") {
foreach(string keyword in Keywords)
{
if(e.Text.Contains(keyword)) { e.Handled = false;
return;
}
} e.Handled = true;

C. private void StackPanel_PreviewTextInput(
object sender, TextCompositionEventArgs e)
{
FrameworkElement feSource = sender as FrameworkElement;
if (feSource.Name == "TxtBoxA" || feSource.Name == "TxtBoxB")
{ foreach(string keyword in Keywords)
{ if(e.Text.Contains(keyword)) {
e.Handled = true;
return; }
} e.Handled = false;
} }

D. private void StackPanel_PreviewTextInput(
object sender, TextCompositionEventArgs e)
{ FrameworkElement feSource = e.Source as FrameworkElement;
if (feSource.Name == "TxtBoxA" || feSource.Name == "TxtBoxB")
{
foreach(string keyword in Keywords)
{ if(e.Text.Contains(keyword)) {
e.Handled = true;
return;
} } e.Handled = false;
}
}

		private void StackPanel_PreviewTextInput(object sender, TextCompositionEventArgs e){
			FrameworkElement feSource = e.Source as FrameworkElement;
			if (feSource.Name == "TxtBoxA" || feSource.Name == "TxtBoxB") {
				foreach (string keyword in Keywords) {
					lbl_info1.Content = e.Text;
//following if statement is my 'enhancement'
					if ( ((((TextBox)feSource).Text)+e.Text).Contains(keyword)) {
						e.Handled = true;
						return;
					}
				} 
				e.Handled = false;
			}
		}

#define DLL_EXPORT extern "C" __declspec(dllexport)

typedef struct device_Struct
{
   int valid;
   int deviceId;
   int version;
   char flashData[100];
}  device_def;

typedef struct module_Struct
{
   device_def module[13];
   int testHdId;
}module_def;

DLL_EXPORT int _stdcall GetModules(int *TestHead,module_def *Module_Def)
{   
   *TestHead=2;
    
   (Module_Def+0)->module[0].valid=1;//Module_Def is array of module_def
   (Module_Def+0)->module[0].deviceId=5;
   (Module_Def+0)->module[0].version=2; 
   strcpy((Module_Def+0)->module[0].flashData,"FlashData");
   Module_Def[0].testHdId=3;
   return 1;
}

[StructLayout(LayoutKind.Sequential,CharSet=CharSet.Ansi)]   
public struct device_Str
{
   public int valid;
   public int deviceId;
   public int version;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
   public string flashData;
};
[StructLayout(LayoutKind.Sequential)]   
public struct module_Str
{
   [MarshalAs(UnmanagedType.ByValArray,SizeConst=13)]
    public device_Str[] module;
    public int testHdId;
};

[DllImport("BCB_DLL.dll")]
public static extern int GetModules(ref int TestHead, module_Str[] Module_Def);

//Main call        
int i,j,NumOfTestHead=0,DeviceID;                        
module_Str[] ModuleDef = new module_Str[4];                       
            
for (i = 0; i < 4; i++)
{
   ModuleDef[i] = new module_Str();                          
   ModuleDef[i].module = new device_Str[13];
   for (j = 0; j < 13; j++)
   {
      ModuleDef[i].module[j] = new device_Str();
   }
}            
GetModules(ref NumOfTestHead,  ModuleDef);
DeviceID=ModuleDef[0].module[0].deviceId;//Do not get the correct value