.NET：从解析数据库中检索数据

Question

I have installed the Parse reference into my MVC Application by downloading it through Package Manager. The reference that has been added is Parse 1.5.5.

ParseClient.Initialize("app_key", ".net_key");
var test = new ParseObject("test");           
test["username"] = "test";
test["password"] = "test";
test.SaveAsync();

ParseQuery<ParseObject> query = ParseObject.GetQuery("test");
ParseObject test1 = query.GetAsync("mVzhilmRJw");

The issue here is that GetAsync method returns ParseQuery type as opposed to ParseObject Type as mentioned in the documentation. Further, the metadata shows that the method GetAsync is not of Async type, which I presumably feel is the root cause.

The following is the error that I'm getting when I try to execute the LINQ version of the above method:

var query1 = ParseObject.GetQuery("test")
    .WhereEqualTo("objectId", "W70H7Ad8rv");
IEnumerable<ParseObject> results = 
    (IEnumerable<Parse.ParseObject>)query1.FindAsync(); 

Error:

Unable to cast object of type 'System.Threading.Tasks.UnwrapPromise 1[System.Collections.Generic.IEnumerable1[Parse.ParseObject]]' to type 'System.Collections.Generic.IEnumerable 1[Parse.ParseObject]'.

I'm trying out Parse as the backend for the first time and not sure if I have included the appropriate references. Further I'm using .NET 4.5 framework, Visual Studio 2012 on a Windows 7 OS. Does this have anything to do with the issue I am facing.

Any help is highly appreciated.

TLDR: How do we retrieve data from Parse in a .NET Web application using .NET 4.5 framework, VS 2012 and what are the references corresponding to Parse that have to be added.

Answer 1

The solution for this issue turned out to be pretty straight forward. It is required that we know what async is all about. This can be found here . It is important that an async method is called within an Async method only. The sample of code can be as seen below

public async void GetData()
{
    ParseClient.Initialize("app_key", ".net_key");
    var query1 = ParseObject.GetQuery("test").WhereEqualTo("objectId", "xxxxxxxx");
    var result = await query1.FindAsync();
}

If you want to know how not to block on call to an async method, you can refer here .