Develop Reference

Unable to change label text when Invoking Method through Reflection in c#

First Look at my code
namespace HealthClub
{
public partial class frmTrainerMaster : Form
{
DataTable dt = new DataTable();
frmHome Home = new frmHome();
public frmTrainerMaster()
{
InitializeComponent();
}
}
private void frmTrainerMaster_Load(object sender, EventArgs e)
{
FillValues("UserNameText");
}
public void FillValues(string UserName)
{
DataTable DT;
SqlCommand cmd = new SqlCommand();
try
{
cmd.Connection = Connections.Connection[UserName];
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "TrainerMaster_pro";
cmd.Parameters.AddWithValue("Option", "FillValues".Trim());
if (Connections.Connection[UserName].State == ConnectionState.Closed)
Connections.Connection[UserName].Open();
SqlDataAdapter adp = new SqlDataAdapter(cmd);
DT = new DataTable();
adp.Fill(DT);
lblId___.Text = DT.Rows[0][0].ToString();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
finally
{
cmd.Parameters.Clear();
cmd.Dispose();
Connections.Connection[UserName].Close();
}
}
}
Now I am calling FillValues() from another class like this
class AnotherClass
{
public void TestMethod(string FormName)
{
Type tp = Type.GetType("HealthClub." + FormName);
object myobj = Activator.CreateInstance(tp);
MethodInfo method = myobj.GetType().GetMethod("FillValues");
object[] parametersArray = new object[] { UserName };
method.Invoke(myobj, parametersArray);
}
}
If you look at the FillValues(), I am assigning the database value to a label. When I am calling it in my first class in page load it's working fine.
But when I am Invoking the medthod from second class, Method invokes but database value does not assign to the label.
What extra effort I need to do ?

There is a class and there is an instance. This is very basic concept you need to understand (not just in C#, but in any objective-oriented language).
// class example
class FrmTrainerMaster { public int SomeProperty { get; set;} }
When you create new instance:
// creates one window
var frmTrainerMasterInstanceOne = new FrmTrainerMaster();
frmTrainerMasterInstanceOne.SomeProperty = 1;
// creates second window
var frmTrainerMasterInstanceTwo = new FrmTrainerMaster();
frmTrainerMasterInstanceTwo.SomeProperty = 2;
Instances are SEPARATE - so at this point querying
// will return 1
Console.Out.WriteLine(frmTrainerMasterInstanceOne.SomeProperty);
// will return 2
Console.Out.WriteLine(frmTrainerMasterInstanceTwo.SomeProperty);
With reflection var myobj = Type.GetType("HealthClub.FrmTrainerMaster"); is equal to var myobj = new FrmTrainerMaster(); so by doing anything with myobj, you still can't affect frmTrainerMasterInstanceOne or frmTrainerMasterInstanceTwo.
What do you need is actually method how to pass reference to instance (of FrmTrainerMaster class) to place where you need it (lets call it AnotherForm), there is no magic list of all instances for given class unless you explicitly build it.
public partial class FrmTrainerMaster : Form
{
public void FillValues(string userName) { ... }
}
One way is via constructor injection (generally proffered - since at time when object (AnotherForm) is constructed you have it in valid state (i.e. with all dependencies initialized).
public class AnotherForm : Form {
private readonly FrmTrainMaster _frmTrainMaster;
public AnotherForm(FrmTrainMaster frmTrainMaster) {
if (frmTrainMaster == null) {
throw new ArgumentNullException(nameof(frmTrainMaster));
}
_frmTrainMaster = frmTrainMaster;
}
}
Or via setter injection:
public class AnotherForm : Form {
private FrmTrainMaster _frmTrainMaster;
public FrmTrainMaster MasterForm { set { _frmTrainMaster = value; } }
}
Either way the reflection is not necessary at all. At any place in your AnotherForm you can just call
class AnotherForm : Form {
...
public void FooMethodThatCallFillValues() {
_frmTrainMaster.FillValues("...");
}
}

The name 'functionname' does not exist in the current context

When trying to compile my c# windows app I am getting the following error:
The name 'GetActiveLB' does not exist in the current context
Here's the code that calls that function:
using F5LTMMaintenance;
......
private void btnLBSetA_Click(object sender, EventArgs e)
{
List<string> range = GetActiveLB();
foreach (string item in range)
{
// Do something with item
}
}
Then I have a class with the following:
namespace F5LTMMaintenance
{
public class F5LTM<T>
{
public List<T> GetActiveLB()
{
var client = new RestClient("mylb.domain.local");
var request = new RestRequest("mgmt/tm/cm/failover-status", Method.GET);
var queryResult = client.Execute<List<T>>(request).Data;
return queryResult == null ? new List<T>() : queryResult;
}
}
}
The GetActiveLB function does exist, its a public function so why am I getting this error? Any help would be appreciated.

It has to be used with an instance of F5LTM<T>.
e.g.:
var f5ltm = new F5LTM<string>();
List<string> range = f5ltm.GetActiveLB();
Alternatively, if you declare it as static like this:
public class F5LTM //not generic here
{
public static List<T> GetActiveLB<T>() //generic here and static
{
//unchanged
}
}
Usage:
List<string> range = F5LTM.GetActiveLB<string>();
Or with C# 6 using static syntax:
using static F5LTMMaintenance.F5LTM; //at top of file
List<string> range = GetActiveLB<string>();
This is as close as you can get to the code you posted.

Yes it's a public function but it's defined inside a different class than your calling event handler class. You need to create a instance of your class F5LTM<T> and on that instance call your method GetActiveLB() rather like
private void btnLBSetA_Click(object sender, EventArgs e)
{
F5LTM<Type> test = new F5LTM<Type>();
List<string> range = test.GetActiveLB();

You will need an instance of your F5LTM class (say typF5LTM), to be able to call typF5LTM.GetActiveLB(). Or you need to make GetActiveLB a static function to be able to call it without an instance like F5LTM.GetActiveLB();

As another poster pointed out, you have to call the method on the class.
F5LTM<string> listItems = new F5LTM<string>();
List<string> range = listItems.GetActiveLB();

How to write test case for protected method throwing exception?

i am working with visual studio and writing Nunit test cases.
While Writing test cases i encountered a class which is having a protected method and that method so throwing an exception of "NotImplementedException" type.
I tried to use Invoke key-word but Ncover is not cover that portion.
I also tried to use try catch but my code reviewer is saying not to use try catch block in test cases.
So, friend is there any other way to write test case for such type of issue.
I am mentioning the class and test cases, please tell me how to solve it.
Class File:-
public class UpdateMacActivityPriorityTranslator : EntityMapperTranslator<object, CSUpdateMACActivityPriorityResponseType>
{
protected override CSUpdateMACActivityPriorityResponseType BusinessToService(IEntityTranslatorService service, object value)
{
throw new NotImplementedException();
}
}
Test case:-
public void BusinessToServiceTest()
{
var updateMacActivityPriorityTranslator = new UpdateMacActivityPriorityTranslator();
var service = MockRepository.GenerateStub<IEntityTranslatorService>();
var value = new object();
var invokeProtectedBusinessToService = new PrivateObject(updateMacActivityPriorityTranslator,new PrivateType( typeof(UpdateMacActivityPriorityTranslator)));
NUnit.Framework.Assert.Throws<NotImplementedException>(
() =>
invokeProtectedBusinessToService.Invoke("BusinessToService",
new object[] { service, value }));
}

If your class (fixture) containing the test method BusinessToServiceTest already derives from (has as base class) UpdateMacActivityPriorityTranslator, I guess you could just do:
public void BusinessToServiceTest()
{
var updateMacActivityPriorityTranslator = new UpdateMacActivityPriorityTranslator();
var service = MockRepository.GenerateStub<IEntityTranslatorService>();
var value = new object();
NUnit.Framework.Assert.Throws<NotImplementedException>(
() => updateMacActivityPriorityTranslator.BusinessToService(service, value)
);
}
or you could just use this instead of updateMacActivityPriorityTranslator, so:
public void BusinessToServiceTest()
{
var service = MockRepository.GenerateStub<IEntityTranslatorService>();
var value = new object();
NUnit.Framework.Assert.Throws<NotImplementedException>(
() => BusinessToService(service, value)
);
}

In your test fixture, implement a private nested class that inherits from UpdateMacActivityPriorityTranslator and exposes the protected method via a public test method:
private class TestUpdateMacActivityPriorityTranslator : UpdateMacActivityPriorityTranslator
{
public CSUpdateMACActivityPriorityResponseType TestBusinessToService(IEntityTranslatorService service, object value)
{
return this.BusinessToService(service, value);
}
}
With that you can test the protected method through the test class and naturally call the method.
var translator = new TestUpdateMacActivityPriorityTranslator();
Assert.Catch<NotImplementedException>(() => translator.TestBusinessToService(null, null));

calling method of a web page without instantiating the page

In my application we have an aspx page frmwebform1.
This page has a static method GetmyData() which calls a helper class HelperClass
But the problem with the code is that when we call the method GetHelperData(), in this
helper class it instantiates frmwebform1 in order to get its method FillGrid().
The problem is when it instantiates frmwebform1 we are loosing entityId and entityType values.
Is there any way I could call the method FillGrid() without instantiating the frmwebform1 page. Unfortunately I cannot make the FillGrid() method as static, as it
will compromise our data.
Thanks for you help in advance.
//frmwebform1.aspx.cs
public partial class frmwebform1 : System.Web.UI.Page
{
string entityId;
string entityType;
protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString["entityId"] != null)
{
entityType = Request.QueryString["entityType"].ToString().ToUpper();
entityId = Request.QueryString["entityId"].ToString();
}
if (!IsPostBack)
{
grdMygrid.DataSource = FillGrid();
grdMygrid.DataBind();
}
}
public DataTable FillGrid()
{
string server = HttpContext.Current.Session["Server"].ToString();
string database = HttpContext.Current.Session["Database"].ToString();
string usrID =HttpContext.Current.Session["user_ID"].ToString();
Data tr = new getData(server, database, usrID);
DataTable dt = tr.getAllEntities(entityId);
return dt;
}
[WebMethod] //AJAX page method
public static List<class1> GetmyData()
{
HelperClass helper = new HelperClass();
return helper.GetHelperData();
}
}
//Second Class
public class HelperClass
{
public List<class1> GetHelperData()
{
frmwebform1 form1 = new frmwebform1();
DataTable dt = form1.FillGrid();
List<class1> list = new List<class1>();
class1 item;
foreach (DataRow dr in dt.Rows)
{
item = new TaxHistory();
item.txr_guid = dr["txr_guid"].ToString();
item.Amount = string.Format("{0}", dr["Amount"]);
item.Email = dr["EmailAddress"].ToString();
item.Date = dr["date"].ToString();
item.user = dr["user"].ToString();
list.Add(item);
}
return list;
}
}

Extract that method from the Page class because it clearly should not be there as it seems to be of a different responsibility:
How do we determine an object's responsibility in OOP?
Create a static class and put that method there.

Make the FillGrid method static.

Rather than having method that fetches data from the db in page class and calling it from some other class is not good thing. If you know layered architecture, you should move that method to Data Access Layer and call that method from page method, which will return you DataTable.
I hope it makes sense :)

I used PageMethods from Javascript. which solved my issue.
Thanks for all your answers.

Moq: how to verify a function that takes in a object created within a method

I have the following method;
public class MyClass
{
public Repository UserRepository { get; set; }
public void CreateUser(Message someMsg)
{
if (someMsg.CanCreate)
{
var obj = new object();
UserRepository.Save(obj)
}
}
}
In my test case, I used Moq to mock out the ObjRepository and I wanted to to call verify on the "Save()" method. However, the save method takes in a object that is created within the method under test, which I cannot mock.
Is there anyway around this using Moq? I am doing this wrong?

You can have the following setup on your mock:
objRepMock.Setup(or => or.Save(It.IsAny<object>()).Callback(obj => {
// Do asserts on the object here
}

marcind got the ball rolling but I thought I'd put more code in. Your test would look like this:
var objMock = new Mock<Repository>();
objMock.Setup(x=>x.Save(It.IsAny<object>)).Verifiable();
var myclass = new MyClass{Repository = objMock.object};
var mymessage = new Mock<Message>();
myclass.CreateUser(mymessage.object);
objMock.Verify(x=>x.Save(It.IsAny<object>), Times.AtLeastOnce);

You could use dependency injection.
public Repository ObjRepository { get; set;}
public void doStuff()
{
var obj = new object();
doStuff(obj);
}
public void doStuff(Object obj)
{
ObjRepository.Save(obj)
}