如何使用C＃在for循环中播种数据

Question

I have the following class in C#:

public partial class Application
{
    public Application()
    {
        this.TestAccounts = new List<TestAccount>();
    }

    public int ApplicationId { get; set; }
    public string Name { get; set; }
    public byte[] RowVersion { get; set; }
    public System.DateTime ModifiedDate { get; set; }
    public virtual ICollection<TestAccount> TestAccounts { get; set; }
}

I would like to insert a few records with the application names of "aa", "bb" and "xx" using something like the following:

List<Application> applications;

public void seedData() {
    var a = new Application { Name = "xx" };
    applications.Add(a);
}

Is there a way that I can enclose the line that creates a new Application record in a for loop and have it then sequence through and insert the three applications rather than me coding them one by one.

Answer 1

You can use LINQ for this:

var names = new[] {"A", "B", "C"};
var apps = names.Select(x => new Application { Name = x });
applications.AddRange(apps);

Answer 2

If I understand the question correctly, then your seedData() method could look something like this:

public void seedData()
{
    const string[] names = new string[] { "xx", "bb", "xx" };
    foreach (string name in names)
        applications.Add(new Application { Name = name });
}

Answer 3

You can use object or collection initializers

List<Application> applications = new List<Application>()
{ 
  new Application(){Name="aa"}, 
  new Application(){Name="bb"}, 
  new Application(){Name="xx"}
};

no need to store the app names in a separate array and loop over it to initialize.
I think also that the resulting code is more clear.

Answer 4

If you would like to use a for loop, here is one way to do this:

var names = new List<string>(new string[] { "aa", "bb", "xx" });

for(int i = 0; i < 3; i++)
{
    var a = new Application { Name = names[i] };
    applications.Add(a);
}

Answer 5

You can use:

    public static IList<Application> CreatesApp(IEnumerable<string> names)
    {
      return names == null ? new List<Application>() : 
             names.Select(name => new Application() { Name = name }).ToList();
    }

Answer 6

Use threads. and .join

ex create a function which creates thread and returns its reference ie: createAppThread(Application app)

so your for loop can be

//code from Cuong Le's answer
names = new[] {"A", "B", "C"};
for (int i=0;i<names.length();i++){
  Application app=new Application { Name = "xx" };//create your app object
  Thread th = createAppThread(app);
  Thread.join(th);

}

this method may block the ui thread for some time but it will work.