I know templates are common within c/c++ however I am currently trying to translate an old VB code our company uses up to a c# equivalent which brings me to my problem....
VB is an type unsafe language so we come across things like
Public Elements As New Collection
so given the line above I need to translate that to a List.. Given that a Collection can be anything from a List to a map I need to template this as efficiently as possible. I was thinking of for first draft ignoring the map option entirely and just making it a List however from my understanding Templates don't truly exist within C#... The below code is what I came up with so far and while it compiles (I have not gotten to a testing point in the rest of the code yet) I don't know if it would actually work...
Public List<ValueType> Elements = new List<ValueType>();
can anyone offer input on if this would work as a generic list where type is determined at input or if I need to change this so the constructor would look more like
Public List<ValueType> Elements = new List<typeof(foo)>();
if the above is confusing I am sorry it is for me as well, and I will try and clarify as questions come in.
this question is no longer relevant, I was able to go into the source of the calling code and determine what variable types that the lists need to support.
Related
I'm trying to save some oxyplots into a list where I can then later generate a pdf or png file for printing to a printer. Is this something that is possible?
I have two classes; one is a plotUsercontrol and the other being a Baseplot.
Also, I did not implement the oxyplots feature of the app so I'm not fully aware of the differences between PlotModel and PlotView.
In my snippet PlotUserControl. I have the following function which I created to grab all the plots from the BasePlot. I declared it as void because I was not sure what type to declare the Data type for the list and function as.
public void getPlots()
{
foreach(var plot in plots)
{
Console.WriteLine(" ");
Console.WriteLine(plot.getImage());
}
}
Bellow is just a fucntion from my baseplot that gets the PlotModel. Also I wasn't sure whether to return the plotModel or the plotView.
public PlotModel getImage()
{
return this.plotModel;
}
I hope this make sense. New to c#.
Do you want to safe your images or the plots into a list? If you want to save plots into a list, that's already done (plots).
However if you want to save images into a list that's a bit different but very easy. I suggest you take a look at List<T>. I can supply you with method that will do all the work but it is so easy that i think you can manage to set up the list on your own.
Here is a quick rundown tho: List<T> will create a list which allows you to save objects of the datatype T inside of it. T is a so-called generic type which means you can hand it every data type that can be instantiated.
Hint: T would be PlotModel in your example.
If you need any more help, feel free to contact me but I think you can manage creating said list on your own.
This is the link to the Microsoft Docs of List<T>, but imo they are not the best docs for beginners. Just look for some tutorials on Google.
Another tip tho, rename your functions. In C# first letters of words in method names are uppercase (e.g: GetPlots(), GetImage()). This is just a common naming style although you can stick to lowercase.
I have a (not quite valid) CSV file that contains rows of multiple types. Any record could be one of about 6 different types and each type has a different number of properties. The first part of any row contains the timestamp and the type of record, followed by a standard CSV of the data.
Example
1456057920 PERSON, Ted Danson, 123 Fake Street, 555-123-3214, blah
1476195120 PLACE, Detroit, Michigan, 12345
1440581532 THING, Bucket, Has holes, Not a good bucket
And to make matters more complex, I need to be able to do different things with the records depending on certain criteria. So a PERSON type can be automatically inserted into a DB without user input, but a THING type would be displayed on screen for the user to review and approve before adding to DB and continuing the parse, etc.
Normally, I would use a library like CsvHelper to map the records to a type, but in this case since the types could be different, and the first part uses a space instead of comma, I dont know how to do that with a standard CSV library. So currently how I am doing it each loop is:
String split based off comma.
Split the first array item by the space.
Use a switch statement to determine the type and create the object.
Put that object into a List of type object.
Get confused as to where to go now because i now have a list of various types and will have to use yet another switch or if to determine the next parts.
I don't really know for sure if I will actually need that List but I have a feeling the user will want the ability to manually flip through records in the file.
By this point, this is starting to make for very long, confusing code, and my gut feeling tells me there has to be a cleaner way to do this. I thought maybe using Type.GetType(string) would help simplify the code some, but this seems like it might be terribly inefficient in a loop with 10k+ records and might make things even more confusing. I then thought maybe making some interfaces might help, but I'm not the greatest at using interfaces in this context and I seem to end up in about this same situation.
So what would be a more manageable way to parse this file? Are there any C# parsing libraries out there that would be able to handle something like this?
You can implement an IRecord interface that has a Timestamp property and a Process method (perhaps others as well).
Then, implement concrete types for each type of record.
Use a switch statement to determine the type and create and populate the correct concrete type.
Place each object in a List
After that you can do whatever you need. Some examples:
Loop through each item and call Process() to handle it.
Use linq .OfType<{concrete type}> to segment the list. (Warning with 10k
records, this would be slow since it would traverse the entire list for each concrete type.)
Use an overridden ToString method to give a single text representation of the IRecord
If using WPF, you can define a datatype template for each concrete type, bind an ItemsControl derivative to a collection of IRecords and your "detail" display (e.g. ListItem or separate ContentControl) will automagically display the item using the correct DataTemplate
Continuing in my comment - well that depends. What u described is actually pretty good for starters, u can of course expand it to a series of factories one for each object type - so that you move from explicit switch into searching for first factory that can parse a line. Might prove useful if u are looking to adding more object types in the future - you just add then another factory for new kind of object. Up to you if these objects should share a common interface. Interface is used generally to define a a behavior, so it doesn't seem so. Maybe you should rather just a Dictionary? You need to ask urself if you actually need strongly typed objects here? Maybe what you need is a simple class with ObjectType property and Dictionary of properties with some helper methods for easy typed properties access like GetBool, GetInt or generic Get?
It's very possible that I just don't understand the problem space, but I'm having trouble figuring out the MEF (Editor Classifier project).
I've created (piecing together the Walkthrough guides from MSDN https://msdn.microsoft.com/en-us/library/ee197665.aspx) a syntax highligher for Informix Stored Procedure language.
One major problem I have is - I want to be able to find all instances of the keyword "DEFINE" and populate the word directly following it into the Statement Completion extension I have (currently it's populated from a defined list of words).
Much like C#'s native support - when you define a variable, it becomes available in the autocompletion dropdown.
I got rid of the in class hardcoding (from the walkthrough) and my completion words are defined like this:
List<Completion> completions = new List<Completion>();
CompletionTags completionTags = new CompletionTags();
foreach (string completionTag in completionTags.completionTags)
{
completions.Add(new Completion(completionTag));
};
My CompletionTags class is pretty simple:
class CompletionTags
{
public List completionTags;
public CompletionTags()
{
this.completionTags = new List<string> {
// SQL keywords
"COUNT",
"FROM",
"HAVING",
};
}
I know WHAT I need to do. I somehow need to hijack the buffer when it changes and find all occurrences of 'DEFINE ([a-zA-Z0-9_]{1,})' and add \1 to the completionTags list.
I have no idea HOW to do this. Any pointers in the right (or any) direction at this point would be greatly appreciated.
Be kind - we've all been out of our depth at some stage (I've been programming in C# now for 3 days)...
Reading this answer will be helpful.
Look at:
XML Editor IntelliSense Features
Schema Cache
i´m trying to query a DataTable object without specifying the fields, like this :
var linqdata = from ItemA in ItemData.AsEnumerable()
select ItemA
but the returning type is
System.Data.EnumerableRowCollection<System.Data.DataRow>
and I need the following returning type
System.Data.EnumerableRowCollection<<object,object>>
(like the standard anonymous type)
Any idea?
Thanks
If I understand you correctly, you'd like to get a collection of objects that you don't need to define in your code but that are usable in a strongly typed fashion. Sadly, no you can't.
An anonymous type seems like some kind of variant or dynamic object, but it is in fact a strongly typed class that is defined at compile time. .NET defines the type for you automatically behind the scenes. In order for .net to be able to do this, it has to have some clue from the code with which to infer the type definition. It has to have something like:
from ItemA in ItemData.AsEnumerable()
select ItemA.Item("Name"), ItemA.Item("Email")
so it knows what members to define. There's no way to get around it, the information has to logically be there for the anonymous type to be defined.
Depending on why exactly your are trying to do this, there are some options.
If you want intellisense while still encapsulating your data access, you can return xml instead of a datatable from your encapsulated data access class. (You can convert data tables to xml very easily. You'll want to use the new System.Xml.Linq classes like the XElement. They're great!) Then you can use VS2008's ability to create an xsd schema from xml. Then use/import that schema at the top of your code page, and you have intellisense.
If you have to have an object an with properties for your data, but don't want to define a class/structure for them, you'll love the new dynamic objects coming in C#4.0/VB10. You have object properties based on what the sql returns, but you won't have intellisense. There is also a performance cost to this, but (a) that might not matter for your situation and (b) it actually is not so bad in some situations.
If you're just trying to avoid making a lot of classes, consider defining structs/structures on the same code file, beneath your class definition. When you add more columns to your result set, it's easy to adjust a struct with more public fields.
In short you can have any two of the following three: (a) dynamic, (b) strontly-typed objects, (3) intellisense. But not all three.
There is one way to accomplish what you want, but it required knowledge of dynamic linq. You would build the query during run-time and then use it. I am no expert and have never really played around with it, but here is a link to Scott Guthrie's blog about it - Dynamic Linq. Hope that helps.
Wade
I am working on a custom ArcGIS Desktop tool project and I would like to implement an automated linear referencing feature in it. To make a long story short, I would like to display problematic segments along a route and show the severity by using a color code (say green, yellow, red, etc.). I know this is a pretty common scenario and have come to understand that the "right way" of accomplishing this task is to create a linear event table which will allow me to assign different codes to certain route segments. Some of my colleagues know how to do it manually but I can't seem to find any way to replicate this programaticaly.
The current tool is written in C# and already performs all the needed calculations to determine the problematic areas. The problem mainly is that I don't know where to start since I don't know a lot about ArcObjects. Any code sample or suggestion is welcome (C# is preferred but C++, VB and others will surely help me anyway).
EDIT :
I'm trying to use the MakeRouteEventLayer tool but can't seem to get the different pre-conditions met. The routes are hosted on an SDE server. So far, I am establishing a connection this way :
ESRI.ArcGIS.esriSystem.IPropertySet pConnectionProperties = new ESRI.ArcGIS.esriSystem.PropertySet();
ESRI.ArcGIS.Geodatabase.IWorkspaceFactory pWorkspaceFactory;
ESRI.ArcGIS.Geodatabase.IWorkspace pWorkspace;
ESRI.ArcGIS.Location.ILocatorManager pLocatorManager;
ESRI.ArcGIS.Location.IDatabaseLocatorWorkspace pDatabaseLocatorWorkspace;
pConnectionProperties.SetProperty("server", "xxxx");
pConnectionProperties.SetProperty("instance", "yyyy");
pConnectionProperties.SetProperty("database", "zzzz");
pConnectionProperties.SetProperty("AUTHENTICATION_MODE", "OSA");
pConnectionProperties.SetProperty("version", "dbo.DEFAULT");
pWorkspaceFactory = new ESRI.ArcGIS.DataSourcesGDB.SdeWorkspaceFactory();
pWorkspace = pWorkspaceFactory.Open(pConnectionProperties, 0);
pLocatorManager = new ESRI.ArcGIS.Location.LocatorManager();
pDatabaseLocatorWorkspace = (ESRI.ArcGIS.Location.IDatabaseLocatorWorkspace)pLocatorManager.GetLocatorWorkspace(pWorkspace);
Now I am stuck trying to prepare everything for MakeRouteEventLayer's constructor. I can't seem to find how i'm supposed to get the Feature Layer to pass as the Input Route Features. Also, I don't understand how to create an event table properly. I can't seem to find any exemple relating to what I am trying to accomplish aside from this one which I don't understand since it isn't documented/commented and the datatypes are not mentionned.
I'm not entirely certain what it is you want to do. If you want to get Linear Referencing values or manipulate them directly in a feature class that already has linear referencing defined, that's pretty straight forward.
IFeatureClass fc = ....;
IFeature feature = fc.GetFeature(...);
IMSegmentation3 seg = (IMSegmentation3)feature;
... blah ...
If you need to create a Feature class with linear referencing, you should start witht he "Geoprocessing" tools in the ArcToolbox. If the out-of-the-box tools can do most of what you need, this will minimize your coding.
I would strongly recommend trying to figure what you need to do with ArcMap if at all possible... then backing out the ArcObjects.
Linear Referencing API
Linear Referencing Toolbox
Understanding Linear Referencing