Is there some shortcut way of handling multiple properties on a class (say 50 spanning string, int, datetime, etc). They will all have the same simple declaration such as
private int myInt;
public int MyInt
{ get { return myInt; }
set { myInt = value; }
}
private datetime someDate;
public datetime SomeDate
{ get { return someDate; }
set { someDate = value; }
}
The reason, is I have a class that will be "bound" to data entry textbox type fields and such. By just making them "public" doesn't work as it wont bind to a field, but will if it's a property with applicable get/set. I just think it's a pain to go through such efforts when it's the same repetition over and over, and believe there is a shorter / more simplified method. I just don't have another mentor to learn from and know that S/O has plenty to help out.
For the current situation I'm in, requires me to only work with .Net 2.0 max... Some restrictions based on handheld devices not yet capable of running 3.0, 3.5, etc.
In C# 3 or higher, you can use auto-implemented properties:
public int MyInt { get; set; }
In VS2010 & 2008 you can right click on the private field, select Refactor->Encapsulate Field.
You will still have to do it field by field, but it has got some smarts in it (with regards to choosing a publicly viewable name), and you can do it all with no typing.
Follow up: i see that the answer from Josh M shows you the keyboard shortcut to do the same thing.
Instead of using fields use properties to begin with:
public int MyInt { get; set }
public DateTime SomeDate { get; set; }
Try CTRL+R+E while on the field.
See more great shortcuts in this blog post.
I don't think there is any shortcut to create fields (other than manually typing it), though it is possible to create properties for "existing" fields in a class. So, in this case you will have write 50 fields, and then you can ask VS to auto-generate the properties for you. Even better if you have Resharper (i think, alt+insert will do the job).
If you have a list of columns/fields and their type, then you can use CodeDom. And then auto-generate the whole class, with all the fields and properties based on the list of columns you have provided.
You said you're stuck with .NET 2.0. Please note that you can use some C# 3.0 features but still target .NET 2.0 Framework. So as long as you use VS2008 and set the target to .NET 2.0 you can use autoprops (and a few other cool features of C# 3.0). Here is a bunch of links on this topic:
http://weblogs.asp.net/shahar/archive/2008/01/23/use-c-3-features-from-c-2-and-net-2-0-code.aspx
http://www.danielmoth.com/Blog/Using-Extension-Methods-In-Fx-20-Projects.aspx
http://www.developer.com/net/csharp/article.php/3598381/The-New-Lambda-Expressions-Feature-in-C-30.htm
type propfull then press TAB twice
Related
Resharper provides a feature to create and initialize an autoproperty from a constructor parameter.
By default, the generated property is of the form:
public int Foo { get; set; }
Is it possible to modify the accessors to have this instead?
protected int Foo { get; private set; }
I checked with JetBrains and this is what they said:
Hi Jesse,
No, it is not possible in the currently. You are welcome, however, to log a feature request in our
issue tracker
So the answer is: No.
To generate this property I guess you are using the prop template
So you can either change it, or create a new one of your own
Go to ReSharper Menu -> Templates Explorer
Choose C# and look for prop , you can click edit and change it
But maybe the best way is to create a new one if you sometimes want default properties
Click new template and write that
protected $TYPE$ $NAME$ { get; private set; }
In the shortcut field type what you want, like prprop for example and save it.
Now open a file and type prprod, tab twice and you got the protected propertiy with private setter
If you are not using templates or snippets but the "Create auto-property from constructor" it seems it's impossible to change the access modifier, the only way to change it is when you use
Resharper -> Edit -> Generate Code ...
Then from there what you choose to generate you can change access modifiers or choose if it's read only.
I would like to use the DebuggerTypeProxy attribute to show, in Debug, a class using Datatable.
I try to better explain what I mean.
I can tell VS to show a class using another proxy class.
So if I have a list I can tell him to visualize that list after putting all the data's in a Datatable. So I can use the standard DebugVisualizer for datatables.
There are a few ways to provide custom debugging visualization,
Use [DebuggerDisplay] attribute
[DebuggerDisplay("Point {X}:{Y}")]
public class Point
{
public int X {get;set;}
public int Y {get;set;}
}
use DebuggerBrowsableDisplay attribute and set the State property to DebuggerBrowsableState.RootHidden - it will alow you to show collections like you have already pressed +
DebuggerTypeProxy attribute - for any custom visualizer.
But personally i wouldnt bother with writing a custom visualizer for the problem that you are describing - there are already debugging products that can do it for you.
You can download OzCode, VS extencion that is still free in its beta and use its Reveal feature:
http://o.oz-code.com/features#reveal
It seems to be exactly what you need :)
SQLCe doesn't support TimeSpan, so I need to save this in some other way. Is it possible to define somewhere a default conversion, like in the DbContext, or would I need to handle this manually in the repositories? I don't like to change my entity classes just because of this.
Btw, I only save TimeSpan of < 24h.
Example would be great if there are some neat tricks.
I know you say you don't want to modify your entities, but if you're using code first this would be pretty simple to do by modifying your entities :)
You could define a property that isn't mapped into the database, that uses another property as its backing store. In this example, TickCount would get saved in the database, but everything else could access Span which exposes TickCount as a TimeSpan struct.
public long TickCount { get; set; }
[NotMapped]
public TimeSpan Span {
get {
return new TimeSpan(TickCount);
}
set {
TickCount = value.Ticks;
}
}
Pretty old but in case anyone ever needs this, I have cloned and modified System.Data.SQLite in order to support TimeSpan properties (mapped to sqlite TIME columns)
You can find the source at https://github.com/arielflashner/System.Data.SQLite
Well, it seems this is basically NOT POSSIBLE.
A TimeSpan property must be marked NotMapped, or by fluent Ignore (then saved as per Steve's answer).
At least that's my understanding now.
EF does not support type mapping or type conversion..
https://stackoverflow.com/a/12053328
Btw, NHibernate maps TimeSpan to integer by default, when using SqLite. No conversions or tricks needed there. Not sure about other databases.
I'm facing a problem that I don't know how to solve and am hoping the community can help.
I'm writing an app that manages "Lead" objects. (These are sales leads.) One part of my program will import leads from a text file. Now, the text file contains lots of potential leads, some of which I will want to import and some of which I won't.
For ease of programming (and use), I'm parsing the text file into a List<Lead> object, and using a DataGridView to display the leads by setting the DataSource property of the DataGridView.
What I want to do is add a column to the grid, called "Import," with a checkbox that the user can check to indicate whether or not each lead should be imported.
My first thought is to derive a class from Lead:
public Class LeadWithImportCheckbox : Lead
{
bool bImport = false;
public bool Import
{
get { return bImport;}
set { bImport = value;}
}
}
However, the parsing engine returns a list of Lead objects. I can't downcast a Lead to a LeadWithImportCheckbox. This fails:
LeadWithImportCheckbox newLead = (LeadWithImportCheckbox)LeadFromParsingEngine;
This is an invalid cast.
The other option I see is to create a constructor for LeadWithImportCheckbox:
public LeadWithImportCheckbox(Lead newlead)
{
base.Property1 = newlead.Property1;
base.Property2 = newlead.Property2;
....
base.Property_n = newlead.Property_n;
}
This is problematic for two reasons. One, the Lead object has several dozen properties and writing this constructor is a PITA.
But worse, if I ever change the underlying structure of Lead, I need to remember to go back and change this constructor for LeadWithImportCheckbox. This is a danger to my code maintenance.
Is there a better way of accomplishing my goal?
or, to avoid the PITA aspect, use reflection... (try this...)
EDIT: use property, not Field as I had originally written...
public class NewLead : Lead
{
public bool Insert;
public NewLead(Lead lead, bool insert)
{
Insert = insert;
foreach (PropertyInfo pi in typeof(Lead).GetProperties())
GetType().GetProperty(pi.Name).SetValue
(this, pi.GetValue(lead,null), null);
}
}
public class LeadListItem
{
public Lead Lead { get; set; }
public bool ShouldImport { get; set; }
}
i.e. don't copy the Lead object's contents, just store a reference to it in a new LeadListItem object, which adds extra info "outside" the original object.
If you want the properties of Lead to appear in the grid, there is almost certainly a way of doing that. Why not ask that question, instead of downvoting me for telling you the right answer to this question!
A couple options you might have missed:
You could update the Lead object itself to have an Import property (that defaults to false).
You could have your "ImportLead" object treat the Lead as payload (even make it generic, if you want), so you don't need the big constructor.
Build a new Lead object list or enumerable that only contains the objects you want to import in the first place.
You can only downcast, if the object to be downcast is really an object of that type.
An easier way to solve your problem would be to have a DisplayLead class, such as:
public class DisplayLead {
Lead lead;
bool bImport;
}
which would also help you separating stored data from their representation in a GUI.
What you want to do is display the checkbox column on your grid and not have it related at all to your Lead objects. You use the marked columns (and possible the original List) to build a new set of List which will be your import list.
Then handle whatever you wish to do with the newly created List.
Edit: One thing to be careful of when working with lists is the fact every class object is actually only a pointer to the class so if you work with the original list and do something like:
List<Lead> Importable = new List<Lead>();
for(int i=0, i++, i<viewGrid.Count)
if(viewGrid[i].CheckedColumn.Checked)
Importable.Add(OriginalList[i]);
That objects will exist in both lists and if you edit data of a Lead on either list both will be changed.
I cannot downcast to something it is not. If the object was instantiated as a Lead, then it can't be downcast to any derived class. If it were instantiated as a LeadWithImportCheckbox and then returned to your code as Lead, then you can downcast it.
Protip: Check type at runtime with is operator.
There are many ways to do this, but the "right" way pops out because of what you said, here:
For ease of programming (and use), I'm
parsing the text file into a
List object, and using a
DataGridView to display the leads by
setting the DataSource property of the
DataGridView.
What I want to do is add a column to
the grid, called "Import," with a
checkbox that the user can check to
indicate whether or not each lead
should be imported.
Your Lead object stands well on its own, and you want to attach some metadata to it -- you don't want to create another Lead classification (i.e. the LeadWithImportCheckbox class).
So, the best approach in your case is to have a class like so:
public class LeadInfo
{
private Lead lead;
private bool shouldImport;
public LeadInfo(Lead lead)
{
this.lead = lead;
this.ShouldImport = false;
}
public bool ShouldImport
{
get { return shouldImport; }
set { shouldImport = value; }
}
}
This will scale well when you want to add more metadata to your list, like if you want to send yourself email reminders about them every week.
I've seen the correct solution listed so many times I feel like a heel posting it again, but the best way to approach this is to write a wrapper for the Lead object that includes the import flag.
If the properties of the Lead object don't appear in the GridView because you're databinding to the object, then write passthrough properties that mirror the Lead properties on the wrapper object.
The issue is that you want something displayed to the user that isn't an inherent part of the data model. The answer is to wrap the data before presenting it to the user so you can control what they see without changing the underlying model.
If you're concerned that the Lead object will change so many times in the future that changes to the wrapper will be cumbersome, you could look into dynamic code generation based on the Lead object that will automatically generate a wrapper object with the same fields as the Lead object plus the import flag. Though frankly, that's a lot more work than you'll probably need for something as straightforward as this.
As a quick and dirty solution, you can create your 'checkbox' object as a different object that contains an instance of Lead.
public GridLead {
public bool Import { get; set; }
public Lead Lead { get; set; }
}
This way you can easily add more 'grid' properties to this object, while still always retaining a reference to the Lead details without hardcoding property cloning into it.
Recommend you try modifying (upgrading) your imported lead objects.
Try starting with the examples here...
If your Lead class had a copy constructor (e.g. "Lead(Lead otherLead)"), LeadWithImportCheckbox would inherit that and you could just call the base Lead constructor in the LeadWithImportCheckbox constructor - hence no need for LeadWithImportCheckbox to be aware of the details of Lead.
I have a console application that I am rebuilding from C to C#. This application has to be able to support the legacy method of storing information like parameters from a command-line and parameters from a file (called the system parameters) that customize each run. The system parameters file is in plain-text with a simple key-value structure.
My questions are:
Should I combine these different parameters into a single Configuration object?
How would I call this configuration object from the code to store parameters?
How would I call this configuration object from the code to retrieve parameters?
Should this object be strongly-typed?
I will need access to this structure from a lot of different places in the code. What is the most elegant way to retrieve the values in the object without passing the object itself around everywhere?
I have a feeling that it should be a single, strongly-typed object and that it should be an instantiated object that is retrieved from a repository with a static retrieval method however I really want validation of this method.
I would use a single configuration object like the following:
using System;
using System.IO;
using System.Reflection;
public sealed class Setting {
public static int FrameMax { get; set; }
public static string VideoDir { get; set; }
static readonly string SETTINGS = "Settings.ini";
static readonly Setting instance = new Setting();
Setting() {}
static Setting() {
string property = "";
string[] settings = File.ReadAllLines(SETTINGS);
foreach (string s in settings)
try {
string[] split = s.Split(new char[] { ':' }, 2);
if (split.Length != 2)
continue;
property = split[0].Trim();
string value = split[1].Trim();
PropertyInfo propInfo = instance.GetType().GetProperty(property);
switch (propInfo.PropertyType.Name) {
case "Int32":
propInfo.SetValue(null, Convert.ToInt32(value), null);
break;
case "String":
propInfo.SetValue(null, value, null);
break;
}
} catch {
throw new Exception("Invalid setting '" + property + "'");
}
}
}
Since this is a singleton, it will create one and only one instance of itself the first time a public static property is referenced from the Setting object.
When the object is created, it reads from the Settings.ini file. The settings file is a plain-text file with a simple key : value structure that might look like this:
FrameMax : 12
VideoDir : C:\Videos\Best
The object uses reflection to discover each property and to store its initial value. In this example, two properties have been defined:
public static int FrameMax { get; set; }
public static string VideoDir { get; set; }
The code as written handles Int32 and String types. By adding additional case statements to the switch statement, you could easily add support for types like Float and Decimal.
To change a setting, you would use something like:
Setting.FrameMax = 5;
To retrieve a setting, you would use something like:
if (Setting.FrameMax > 10) ...
You'll notice that all the properties are strongly-typed. Also, you don't have to pass the Setting object around, as all the Setting properties are static and always available everywhere.
I hope this idea is helpful.
I like using Settings. These can be generated automatically either by creating a settings file using the Add New File dialog box, or by adding a default settings file from project properties.
Each setting may be in user or application scope, which controls whether or not the user can change them or they are restricted to their default values. They are easily saved with the Save() method and loaded automatically into the static Default property.
This class seems to be for application or user-based settings. I'm looking for per-run settings. Would you still recommend using this class in that case? – x97mdr
Yes. If you have both user/application based settings and per-run settings you should use two different classes - the normal (saved) settings and the per-run settings.
As long as you don't save the per-run settings, you should be safe and settings are still quite easy to use. These are static settings though. If the same application run needs several instances - this is the wrong approach.
I find that whenever I have to deal with a legacy system, sticking with the old format almost always works best. Often times there are other people using the legacy formats for other tasks (like automation of the app, for example), so if you recode the way the application handles inputs, you might break other systems.
On the other hand, if you are pretty confident that you know all the people using the system, and they tell you that they don't care if you change these types of things, I would probably move everything to XML. Besides all the nice features of XML from an application point of view (like being in ASCII so it's easily modified by humans, being self-documenting, etc ...), XML is also time-saving, in that you don't have to write your own I/O or parser. There's already a wide variety of libraries out there, particularly in .NET 3.0/3.5, that do very well. (As you're moving to C#, I'm guessing you're already thinking along these lines :)
So ultimately, you'd have to base your decision on cost-to-implement: if you lower your cost of implementation by moving to XML or similar, make sure that you don't raise other people's cost of implementation to move to your new application framework.
Good luck!
XmlDocument - you can generate a class definition using XSD.exe