I can't find any documentation or examples I can follow to use the SqlBuilder class.
I need to generate sql queries dynamically and I found this class. Would this be the best option?
the best place to start is to checkout the dapper source code from its github repo and have a look at the SqlBuilder code. The SqlBuilder class is only a 200 lines or so and you should be able to make an informed choice on whether it is right for your needed.
An other option is to build your own. I personally went down this route as it made sense. Dapper maps select querys directly to a class if you name your class properties the same as your database or add an attribute such as displayName to map from you can use reflection to get the property names. Put there names and values into a dictionary and you can genarate sql fairly easy from there.
here is something to get you started:
first an example class that you can pass to your sqlbuilder.
public class Foo
{
public Foo()
{
TableName = "Foo";
}
public string TableName { get; set; }
[DisplayName("name")]
public string Name { get; set; }
[SearchField("fooId")]
public int Id { get; set; }
}
This is fairly basic. Idea behind the DisplayName attribute is you can separate the properties out that you want to include in your auto generation. in this case TableName does not have a DisplayName attribute so will not be picked up by the next class. however you can manually use it when generating your sql to get your table name.
public Dictionary<string, object> GetPropertyDictionary()
{
var propDictionary = new Dictionary<string, object>();
var passedType = this.GetType();
foreach (var propertyInfo in passedType.GetProperties())
{
var isDef = Attribute.IsDefined(propertyInfo, typeof(DisplayNameAttribute));
if (isDef)
{
var value = propertyInfo.GetValue(this, null);
if (value != null)
{
var displayNameAttribute =
(DisplayNameAttribute)
Attribute.GetCustomAttribute(propertyInfo, typeof(DisplayNameAttribute));
var displayName = displayNameAttribute.DisplayName;
propDictionary.Add(displayName, value);
}
}
}
return propDictionary;
}
This method looks at the properties for its class and if they are not null and have a displayname attribute will add them to a dictionary with the displayname value as the string component.
This method is designed to work as part of the model class and would need to be modified to work from a separate helper class. Personally I have it and all my other sql generation methods in a Base class that all my models inherit from.
once you have the values in the dictionary you can use this to dynamically generate sql based on the model you pass in. and you can also use it to populate your dapper DynamicParamaters for use with paramiterized sql.
I hope this helps put you on the right path to solving your problems.
Related
I tried to play with Dapper Extension & MS Access and succeeded up to certain extent. My code is listed below. All the functions works properly (Insert/Count/GetList/Delete) except Get & Update. I have summarised the code below. If anybody wants I can paste all the code here
My Product class
public class Products
{
public string ProductNumber { get; set; }
public string Description { get; set; }
}
And in my main class. I tried to get the product and update it as below. con.Get<Products> function returns an exception with "Sequence contains more than one element" message and con.Update<Products> returns an exception with "At least one Key column must be defined".
using (var con = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=test.mdb"))
{
string ProductNumber = "12";
var product4 = con.Get<Products>(ProductNumber);
product4.ProductNumber = "Baz";
con.Update<Products>(product4);
Console.ReadLine();
}
Even though con.Get<Products> fails con.GetList<Products>(predicate) works perfectly. I did follow this link for setup
If DapperExtensions can't infer a key property called ID from your class, you'll need to explicitly specify one via a class mapper. Assuming the ProductNumber is the primary key in the database, the following example class mapper should set the ProductNumber to be the primary key for DapperExtensions.
using Dapper;
using DapperExtensions;
using DapperExtensions.Mapper;
public class ProductsMapper : ClassMapper<Products>
{
public ProductsMapper()
{
Map(x => x.ProductNumber).Key(KeyType.Assigned);
AutoMap();
}
}
This class can sit somewhere within the same assembly as the rest of your code. Dapper Extensions will automatically pick it up. If you have your classes and Dapper code in separate assemblies, you can point it to your mapper with the following line:
DapperExtensions.DapperExtensions.SetMappingAssemblies({ typeof(ProductsMapper).Assembly })
I have an application with a plugin architecture using MEF. For every exported part there is an attribute with the part's name, and I want to have the names translated, because I use these strings to display the available parts in ListBoxes (or the like).
So, I tried to set the 'Name = Strings.SomeText" in the [Export] annotation, but I get the following error:
"An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type"
Is there a solution to this? I find the use of the Metadata very useful (I do lazy loading) and I would not want to redesign everything just to get a few texts translated.
Any ideas? Thanks.
Unfortunately you can't directly provide the translated text to the attributes because an attribute can only contain data that is known at compile time. So you will need to provide some compile time constant value that you can later use to look up the translated test.
One solution would be to pass the resource name to the attribute. Then when you want to display the translated text you grab the resource name, look up the text in the resources and display the result.
For instance your attribute could look something like:
[Export(Name = "SomeText")]
public class MyExport
{
}
Then when you want to display the string you load the resources from the assembly that defines the export and you extract the actual text from the loaded resources. For instance like this (as borrowed from another answer):
var assembly = typeof(MyExport).Assembly;
// Resource file.. namespace.ClassName
var rm = new ResourceManager("MyAssembly.Strings", assembly);
// exportName contains the text provided to the Name property
// of the Export attribute
var text = rm.GetString(exportName);
The one obvious drawback about this solution is that you lose the type-safety that you get from using the Strings.SomeText property.
--------- EDIT ---------
In order to make it a little easier to get the translated text you could create a derivative of the ExportAttribute which takes enough information to extract the translated text. For example the custom ExportAttribute could look like this
public sealed class NamedExportAttribute : ExportAttribute
{
public NamedExportAttribute()
: base()
{
}
public string ResourceName
{
get;
set;
}
public Type ResourceType
{
get;
set;
}
public string ResourceText()
{
var rm = new ResourceManager(ResourceType);
return rm.GetString(ResourceName);
}
}
Using this attribute you can apply it like this
[NamedExport(
ResourceName = "SomeText",
ResourceType = typeof(MyNamespace.Properties.Resources))]
public sealed class MyClass
{
}
Finally when you need to get the translated text you can do this
var attribute = typeof(MyClass).GetCustomAttribute<NamedExportAttribute>();
var text = attribute.ResourceText();
Another option is to use the DisplayAttribute
I use in my force.com application Apex Classes, and many of them have the same structure, I want to make an API to reuse it after.
For exaple, these are two classes :
//first class
public class insererActAct{
public List<Activites_actuelles__c> accts {get; set;}
public insererActAct(ApexPages.StandardController controller){
accts = new List<Activites_actuelles__c>();
accts.add(new Activites_actuelles__c());
}
public void addrow(){
accts.add(new Activites_actuelles__c());
}
public PageReference deleteRow(){
if (accts.size()>1)
{
accts.remove(accts.size()-1);
}
return null;
}
public PageReference save()
{
insert accts;
Assure__c theParent = new Assure__c(id=accts[0].Activites_actuelles__c);
PageReference acctPage = new ApexPages.StandardController(theParent).view();
acctPage.setRedirect(true);
return acctPage;
}
}
//second class
public class insererEnfants{
public List<Enfants__c> accts {get; set;}
public insererEnfants(ApexPages.StandardController controller){
accts = new List<Enfants__c>();
accts.add(new Enfants__c());
}
public void addrow(){
accts.add(new Enfants__c());
}
public PageReference deleteRow(){
if (accts.size()>1)
{
accts.remove(accts.size()-1);
}
return null;
}
public PageReference save()
{
insert accts;
Assure__c theParent = new Assure__c(id=accts[0].Parent__c);
PageReference acctPage = new ApexPages.StandardController(theParent).view();
acctPage.setRedirect(true);
return acctPage;
}
}
Can any one tell me it is possible or not, if yes, how can I do this, please ?
Do you mean you want to write code that works for different kinds of objects, rather than stating the type of object in the code?
It is possible to do this, by declaring your sObject variables with the sObject type, e.g, instead of
public List<Activites_actuelles__c> accts {get; set;}
you would put
public List<sObject> sObjects{get; set;}
and by referencing fields using get and put, e.g. instead of
Account theAccount = new Account();
theAccount.name = 'Fred';
you would put
sObject theSObject = new SObject();
theSObject.put('name', 'Fred');
I've not tried using code like this in a controller extension, but in theory since you can pass in any standard controller you ought to be OK.
You will need to think about how to create the parent object inside the save method, because you will need to pass in what type you want to create. It's quite complicated but it is possible to take in a string representing the object type (e.g. 'Account') and create a new object of that type:
Schema.getGlobalDescribe().get('Account').newSObject()
will get you a new Account. So you could replace 'Account' with any type passed in as a parameter.
For more information look up Dynamic Apex, Dynamic SOQL and Dynamic DML in the documentation.
A word of warning: Passing around object types and field names as strings means that the compiler will not know those types are mentioned in the code. So if you try and delete a custom object or rename a field, salesforce will not warn you that the object or field is in use and will allow you to do the deletion.
Another word of warning: Although this allows code reuse and that is a benefit, you may find it is not worth it. I avoid writing dynamic apex unless I absolutely have to. It is far more complex than ordinary apex and it is therefore difficult to debug and maitain, especially if someone other than yourself has to maintain it.
What are the requirements for a custom data source to be listed in the 'Data Source' drop-down list when adding a Dataset to a .rdlc report in Report Viewer 2010?
As can been seen from the screen grab, for some reason it is listing potential sources from a variety of referenced assemblies, but I can't see an obvious pattern as to why it is selecting these.
The 'GeneralDataSet' makes sense as that is a strongly-typed Dataset class, but I'm pretty sure most of the others are not, yet the design dialog still lists them.
I'm looking to roll my own custom data source and would prefer it to be selectable from this list.
I think it scans your project file looking for methods that return Lists<> and so on.
So something like:
public class Person
{
public string name { get; set; }
public int age { get; set; }
}
public class GetPeople
{
public List<Person> GetPeopleList()
{
return null;
}
public IEnumerable<Person> GetPeopleIEnumerable()
{
return null;
}
public IQueryable<Person> GetPeopleIQueryable()
{
return null;
}
}
All three show up, so take your pick. (Code is just thrashed out, ignore bad names/practices :))
But when you use a ReportViewer, you will need to manually set the datasets. Selecting it inside the report from what I have found just basically tells it what data to expect. So add an ObjectDataSource or just set it in the code behind.
I noticed the dataset does not appear if the source is exposed as a Property and not a method.
ie this fails to be a selectable data source.
public class FooData
{
public List<string> Data {get;set;}
}
but this will show up as a data source
public class FooData
{
public List<string> GetData();
}
I just had a problem with this also,
my class was returning Lists but would not show up in the datasources list.
I then added a parameterless constructor and it started to show up ( there was not one before ) I assmume this is so the reportviewer can create and instance of it.
eg:
public MyObject()
{
}
I've had a similar problem with custom lists which inherit from List.
You can work around it if your system will allow you to inherit without using interfaces. Ours doesn't.
The project containing this class WILL appear in the DataSource dropdown, and the class itself appears in the DataSet dropdown:
public class AccountList : List<AccountData>
{}
This class will NOT appear as a Dataset, which prevents its project from appearing as a DataSource (notice the "I" in front of AccountData):
public class AccountList : List<IAccountData>
{}
This is a pain because other aspects of our system require the lists to inherit from an interface not a concrete class. I don't know why it doesn't work.
I know this must be an age-old, tired question, but I cant seem to find anything thru my trusty friend (aka Google).
I have a .net 3.5 c# winforms app, that presents a user with a login form on application startup. After a successful login, I want to run off to the DB, pull in some user-specific data and hold them (in properties) in a class called AppCurrentUser.cs, that can thereafer be accessed across all classes in the assembly - the purpose here being that I can fill some properties with a once-off data read, instead of making a call to the DB everytime I need to. In a web app, I would usually use Session variables, and I know that the concept of that does not exist in WinForms.
The class structure resembles the following:
public class AppCurrentUser {
public AppCurrentUser() { }
public Guid UserName { get; set; }
public List<string> Roles { get; set; }
public string Firstname { get; set; }
public string Lastname { get; set; }
}
Now, I have some options that I need some expert advice on:
Being a "dumb" class, I should make the properties non-static, instantiate the class and then set the properties...but then I will only be able to access that instance from within the class that it was created in, right?
Logically, I believe that these properties should be static as I will only be using the class once throughout the application (and not creating new instances of it), and it's property values will be "reset" on application close. (If I create an instance of it, I can dispose of it on application close)
How should I structure my class and how do I access its properties across all classes in my assembly? I really would appreciate your honest and valued advice on this!!
Thanks!
Use the singleton pattern here:
public class AppUser
{
private static _current = null;
public static AppUser Current
{
get { return = _current; }
}
public static void Init()
{
if (_current == null)
{
_current = new AppUser();
// Load everything from the DB.
// Name = Dd.GetName();
}
}
public string Name { get; private set; }
}
// App startup.
AppUser.Init();
// Now any form / class / whatever can simply do:
var name = AppUser.Current.Name;
Now the "static" things are thread-unsafe. I'll leave it as an exercise of the reader to figure out how to properly use the lock() syntax to make it thread-safe. You should also handle the case if the Current property is accessed before the call to Init.
It depends on how you setup your architecture. If you're doing all your business logic code inside the actual form (e.g. coupling it to the UI), then you probably want to pass user information in as a parameter when you make a form, then keep a reference to it from within that form. In other words, you'd be implementing a Singleton pattern.
You could also use Dependency Injection, so that every time you request the user object, the dependency injection framework (like StructureMap) will provide you with the right object. -- you could probably use it like a session variable since you'll be working in a stateful environment.
The correct place to store this type of information is in a custom implementation of IIdentity. Any information that you need to identify a user or his access rights can be stored in that object, which is then associated with the current thread and can be queried from the current thread whenever needed.
This principal is illustrated in Rocky Lhotka's CLSA books, or google winforms custom identity.
I'm not convinced this is the right way but you could do something like this (seems to be what you're asking for anyway):
public class Sessions
{
// Variables
private static string _Username;
// properties
public static string Username
{
get
{
return _Username;
}
set
{
_Username = value;
}
}
}
in case the c# is wrong...i'm a vb.net developer...
then you'd just use Sessions.USername etc etc