MongoDB for C#, I started following their tutorial but the compile error I get is on this line:
http://www.mongodb.org/display/DOCS/CSharp+Driver+Quickstart
var update = Update.Set("Name", "Harry");
saying
System.Windows.Forms.Control.Update()' is a 'method', which is not
valid in the given context.
The only difference I see is that they have used a Console Application but I created a C#WinForms applications and pasted their code inside a button click .
Update is simply ambiguous in the context you are using the call. You need to qualify the Update statement to include the namespace it is in.
var update = MongoDB.Driver.Builders.Update.Set("Name", "Harry");
This will probably get annoying, so you can also create an alias in your header.
using U = MongoDB.Driver.Builders.Update;
Then, you can change your statement to be this:
var update = U.Set("Name", "Harry");
I guess your c#WinForms contains an method called Update, which c# tries to access instead of the MongoDB one. Have you checked that you're imported everything needed and that your accessing the right Object?
Related
I have a background in C++ and recently I started working in C#.
I have written following pieces of code (in Visual Studio):
var list_Loads = database.GetData<Load>().ToList();
var test_list = list_Loads.Where(o => (o.Name.Substring(0, 3) == "123")).ToList();
When I run the program and I move my mouse over both lists, first I get the count, which is very useful, but when I ask for the entries, this is what I get:
0 : namespace.Load
1 : namespace.Load
2 : namespace.Load
...
Not very useful, as you can imagine :-)
So my question: how can I show the Name attributes of those objects?
I thought: no problem. I have a background in native visualisers, so it should be rather easy to turn this into useful information, but then it comes:
In order to alter the way that those objects are represented, there is the first proposal to add a [DebuggerDisplay] "tag" to the definition of that class in source code.
However, as those classes are part of a framework I'm just referring to, I don't have access to the source code and hence I can't modify this.
Then I found another solution, which comes down to: "Write an entire C# project, debug, test and install it and it might work" (see documentation on "Custom visualisers of data" on the Microsoft website).
I almost choked in my coffee: writing an entire project, just for altering the view of an object??? (While, in C++, you just create a simple .natvis file, mention the classname and some configuration, launch .nvload and that's it.
Does anybody know a simple way to alter the appearance of C# object, without needing to pass through the whole burden of creating an entire C# project?
By the way, when I try to load a natvis file in Visual Studio immediate window, this is what I get:
.nvload "C:\Temp_Folder\test.natvis"
error CS1525: Invalid expression term '.'
What am I doing wrong?
Thanks in advance
OP (my emphasis):
In order to alter the way that those objects are represented, there is the first proposal to add a [DebuggerDisplay] "tag" to the definition of that class in source code.
However, as those classes are part of a framework I'm just referring to, I don't have access to the source code and hence I can't modify this.
Does anybody know a simple way to alter the appearance of C# object, without needing to pass through the whole burden of creating an entire C# project?
If you just want to specify [DebuggerDisplay] on a type, you don't have to have access to the source code. You can make use of [assembly:DebuggerDisplay()] and control how a type appears in the debugger. The only downside is that [assembly:DebuggerDisplay()] naturally only affects the current assembly whose code your mouse is hovering over. If you wish to use the customised display in other assemblies that you own, then you must repeat the [assembly:DebuggerDisplay()] definition.
Here's an easy before-and-after example with DateTime. I picked DateTime because we generally don't have access to the source code and it has some interesting properties:
var items = new List<DateTime>
{
DateTime.Now.AddDays(-2),
DateTime.Now.AddDays(-1),
DateTime.Now
};
...which on my machine defaults to:
Maybe I'm fussy and I just want to see:
Day of the week and
Day of the year
...I can do that via:
using System.Diagnostics;
[assembly: DebuggerDisplay("{DayOfWeek} {DayOfYear}", Target = typeof(DateTime))]
...which results in:
Example:
namespace DebuggerDisplayTests
{
public class DebuggerDisplayTests
{
public DebuggerDisplayTests()
{
var items = new List<DateTime>
{
DateTime.Now.AddDays(-2),
DateTime.Now.AddDays(-1),
DateTime.Now
};
}
}
.
.
.
}
Overrides
[assembly:DebuggerDisplay()] can also be used as a means to override pre-existing [DebuggerDisplay] on a 3-rd party type. Don't like what style they have chosen? Is the type showing far too much information? Change it with [assembly:DebuggerDisplay()].
I have an app that uses Realm db. I have added a string property to UserRealm named Test.
When I try to run my app it writes
Realms.Exceptions.RealmMigrationNeededException: Migration is required
due to the following errors:
- Property 'UserRealm .Test' has been added.
I'm trying to search on the internet, but almost everywhere the solution is deleting the old database. I dont want to delete the old database, I need to keep it and just add this one column.
This is a Xamarin/C# project.
How can I just simply add a sinle property migration to the realm? It's no problem if the default value is string.Empty.
I Use
Realm nuget 3.4.0,
Realm.Database 3.4.0
Fody 3.3.4
Just add a MigrationCallback to your RealmConfiguration, you do not have to do anything within that callback if no data transformation is needed and you do not need to init new properties to something other than their default values in Realm.
var config = new RealmConfiguration
{
SchemaVersion = 2,
MigrationCallback = (migration, oldSchemaVersion) =>
{
}
};
re: https://realm.io/docs/dotnet/latest#performing-a-migration
I am trying to call a Property called Filter that returns the string of the filter that is applied on a Table on my access application.
My library is:
using AccessApi = Microsoft.Office.Interop.Access;
My code is:
AccessApi.Application ap = (AccessApi.Application)Marshal.GetActiveObject("Access.Application");
string filter = ap.Screen.ActiveDatasheet.Filter;
But then Ambiguity Error occurs. I think I should overload somehow the Method I want to use but I don't know how.
I had the same issue today. My problem was caused by an auto-generated file which is used by Xamarin. The file implemented and declared the same variables as from my code.
Check you solution for auto-generated files.
I have a bit of a weird issue. Working in C# script with SSIS I have developed a need to build a List based off Dynamic Data.
Background
To explain it, a script task is fired that has a variable API URL, this goes off and pulls a JSON string back and then throws it into a strongly typed list using the following code.
var listobject = get_APIData<ApplicationOneDataSet>(url)
The class that does this is long winded and not really needed in the context of this issue.
ApplicationOneDataSet is a strongly typed match to one of the possible JSON results returned by get_APIData.
Now I have a need to change ApplicationOneDataSet to ApplicationTwoDataSet dynamically based on which API URL I pass to the script.
So what I have done is send through a second variable to the script called class name which contains the string "ApplicationDataSetOne" or "ApplicationDataSetTwo" based on which context I call it under.
The Question
My question is how can I dynamically vary this line:
var listobject = get_APIData<ApplicationOneDataSet>(url)
With the string variable passed into the script.
My original thinking was something along the lines of this:
var ClassType = (string) Dts.Variables["AppClassName"].Value;
Type type = Type.GetType(ClassType);
var listobject = get_APIData<type>(url)
Though it doesn't seem to like that. Any tips would be great!
As long as there is exactly two types you can use and you know them at compile time, I would not look further than a simple if. It works, it's easy, everyone understands it.
You can do it totally dynamic at runtime, but that's a huge pain in the... where you don't want it to be. If you really want to go down that rabbit hole, you can find more information here.
I'm not sure I fully understood what you are trying to do, but how about writing an interface ApplicationDataSet and then making a list of it? This way your list is going to be able to contain both types of data.
I'm working on an NHibernate project, and where I had trouble loading collections earlier (http://stackoverflow.com/questions/4213506/c-hibernate-criteria-loading-collection), I now have problems using data.
I'm using C# in combination with the NHibernate and Spring.Net framework, and I get an LazyInitializationException after I load for instance an 'ordercredit', and then accessing an object of the ordercredit.
I use this code for getting the OrderCredit:
OrderCredit oc = CreditService.getOrderCredit(ordercredit.Id);
The code I use for loading is done using a DAO implementation:
[Transaction(TransactionPropagation.Required, ReadOnly = true)]
public OrderCredit GetOrderCredit(long ordercreditid)
{
var creditrules = Session.CreateCriteria(typeof(OrderCredit));
creditrules.Add(Restrictions.Eq("Id", ordercreditid));
return creditrules.List<OrderCredit>()[0];
}
When I run this on my local machine, everything works fine, and I actually intended to load a list of those 'ordercredits', but that went wrong as well, so I tried a simpler step first.
The objects within the 'OrderCredit' are defined as [OneToMany].
When I put this on the testserver, and try to access the 'OrderObject' object of the loaded OrderCredit, I get the error:
NHibernate.LazyInitializationException: Initializing[.OrderObject#5496522]-Could not initialize proxy - no Session.
Code that fails:
Log.Debug(oc.OrderObject.Name);
Code that works:
Log.Debug(oc.Id);
This happens for any object that's part of the OrderCredit, but I am able to access the property fields of the OrderCredit (for instance the OrderCredit.Id).
Also, when I access any of the objects BEFORE I return the data to the original function calling the method, then it does cache the information or so, as I can access it then.
I've read a lot about this problem, like turning off Lazy, but that did not work for me either (or I did that on the wrong place).
The thing that frustrates me most, is the fact that it actually does work on my local machine, and not on the testserver. What could I be doing wrong?
Any help is highly appreciated.
1st update:
I am using now a GenericDao, using the default method of loading 1 ordercredit. I use the following code to load 1 ordercredit by Id.
OrderCredit oc = GenericService.Load<OrderCredit>(Id);
The code that's inside the GenericDAO is the following, BUT it does not end or breaks the session, which means I am able to access the objects attached to the ordercredit:
[Transaction(TransactionPropagation.Supports, ReadOnly = true)]
public T Load<T>(long id) where T : ISaveableObject
{
var obj = Session.Load<T>(id);
return obj;
}
This is nearly the same code as I had in the function which I included earlier in this question.
I'm now really confused because I don't know what it could be that ends the session. I will work with it now as it works, but I want to change it later on, so I can use my function to call the entire collection and access them via a for each loop.
Currently, I use my 'getOrderCredits' function to get the list of OrderCredit objects, and in the foreach, I get the Id, and use the GenericDao.Load to get the actual item, and can access the objects and such. Of course this is not the way it should be and needs to be.
I'd be amazed if I get this solved.
This is a common problem people have when using NHibernate. It happens because:
You open a session
You load an entity from the database which references another entity
You close the session
You try to access a property on your referenced entity
NHibernate tries to lazily load the entity from the database using the same session that loaded the parent entity
The session is closed, so NHibernate throws exceptions like woah.
You have a few options here:
Keep your session open longer, preferably using something like the unit of work pattern, which will give you tighter control.
Eagerly load your referenced entities when you query:
In your case as spring is managing your transaction for you the 2nd option is probably the quickest/easiest solution.
var creditrules = Session.CreateCriteria(typeof(OrderCredit));
creditrules.Add(Restrictions.Eq("Id", ordercreditid))
.SetFetchMode("OrderObject", FetchMode.Eager);
This will load the OrderObject when you load the OrderCredit.