Prev: Help with HttpFileCollection and keeping files in memory
Next: Application Domain
From: Tony Johansson on 16 May 2010 06:47
Hi!

This program is supposed to create these rows dynamically
Hashtable tbl new Hashtable();
tbl.Add("Hi","Hello");
int foo = tbl.Count;

Here I have a simple example that give exception when this row is being
executed
*ConstructorInfo ctor = hashType.GetConstructor(argumentTypes);*
the exception I get is the following when I translated from my native
language
"NullReferenceException was unhandled
the Objectreference has not been given to an instance of an object"

Is it anyone that might have an idea what I have to change ?

static void Main(string[] args)
{
string path =
@"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\mscorlib.dll";
Assembly theAssembly = Assembly.LoadFile(path);

Type hashType = theAssembly.GetType("Hashtable");

Type[] argumentTypes = Type.EmptyTypes;
ConstructorInfo ctor = hashType.GetConstructor(argumentTypes);

object newHash = ctor.Invoke(new object[]{});

MethodInfo method = hashType.GetMethod("Add");
method.Invoke(newHash, new object[] { "Hi", "Hello" });

PropertyInfo property = hashType.GetProperty("Count");
int count = (int)property.GetValue(newHash, null);
}

//Tony


From: Willem van Rumpt on 16 May 2010 06:59
On 16-5-2010 12:47, Tony Johansson wrote:
> Hi!
>
> This program is supposed to create these rows dynamically
> Hashtable tbl new Hashtable();
> tbl.Add("Hi","Hello");
> int foo = tbl.Count;
>
> Here I have a simple example that give exception when this row is being
> executed
> *ConstructorInfo ctor = hashType.GetConstructor(argumentTypes);*
> the exception I get is the following when I translated from my native
> language
> "NullReferenceException was unhandled
> the Objectreference has not been given to an instance of an object"
>
> Is it anyone that might have an idea what I have to change ?
>
> static void Main(string[] args)
> {
> string path =
> @"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\mscorlib.dll";
> Assembly theAssembly = Assembly.LoadFile(path);
>
> Type hashType = theAssembly.GetType("Hashtable");
>
> Type[] argumentTypes = Type.EmptyTypes;
> ConstructorInfo ctor = hashType.GetConstructor(argumentTypes);
>
> object newHash = ctor.Invoke(new object[]{});
>
> MethodInfo method = hashType.GetMethod("Add");
> method.Invoke(newHash, new object[] { "Hi", "Hello" });
>
> PropertyInfo property = hashType.GetProperty("Count");
> int count = (int)property.GetValue(newHash, null);
> }
>
> //Tony
>
>

Most likely because theAssembly.GetType("Hashtable") returns null.
Maybe it's an idea to debug the code and check it yourself?


--
Willem van Rumpt
From: Alberto Poblacion on 16 May 2010 07:14
"Tony Johansson" <johansson.andersson(a)telia.com> wrote in message
news:OYureUO9KHA.5464(a)TK2MSFTNGP05.phx.gbl...
> Type hashType = theAssembly.GetType("Hashtable");
> *ConstructorInfo ctor = hashType.GetConstructor(argumentTypes);*
> "NullReferenceException was unhandled

"Willem van Rumpt" <wdotvandotrumpt(a)skoutsoftdotcom> wrote in message
news:uIXZsbO9KHA.3880(a)TK2MSFTNGP04.phx.gbl...
> Most likely because theAssembly.GetType("Hashtable") returns null.

... and the probable reason why it returns null is that you forgot to
specify the namespace:

theAssembly.GetType("System.Collections.Hashtable")


 | 
Pages: 1
Prev: Help with HttpFileCollection and keeping files in memory
Next: Application Domain