CODEWITHSUNDEEP
xamarinxamarin.forms
Vipin Krishna
Vipin Krishna

Reputation: 365

Xamarin Forms execution returns from await Httpclient PostAsync

I am calling a methodgetaddress();inside viewmodel for getting address information from API. But while debugging, execution returns at var response = await client.PostAsync(base_url + "api_delivery_details", formcontent).ConfigureAwait(false);to the calling method getaddress() but executes the remaining portion later.so getting null result. How to execute all from first time?

public async void Get_branch_products()
    {
        RestClient restClient = new RestClient();            
        getaddresses();  //this is the calling method

        long delivery_fee1 = long.Parse(delivery_fee);
        GrandTotal = Total + (Total * Tax) / 100 + delivery_fee1 ;            
        OnPropertyChanged("GrandTotal");
        tax_amt = (Total * Tax) / 100;
        OnPropertyChanged("tax_amt");
    }


public async void getaddresses()
    {
        ind_vis = true;
        OnPropertyChanged("ind_vis");             
        int user_id = (int)App.Current.Properties["user_id"];
        RestClient restClient = new RestClient();
        var result = await restClient.Get_address(user_id);  //calling restAPI method

        if (result.status == "success")
        {
            ind_vis = false;
            OnPropertyChanged("ind_vis");


public async Task<Address> Get_address(int user_id)
    {
        var formcontent = new FormUrlEncodedContent(new[]
        {
           new KeyValuePair<string,string>("user_id",user_id.ToString())
        });
  //returns from here// var response = await client.PostAsync(base_url + "api_delivery_details", formcontent).ConfigureAwait(false); 
  //executes later// var result = await response.Content.ReadAsStringAsync();
        var Items = JsonConvert.DeserializeObject<Address>(result);
        return Items;
    }

Upvotes: 0

Views: 240

Answers (1)

FreakyAli
FreakyAli

Reputation: 16449

Always remember one thing while creating background threads using async-await, async voids unless a built-in event handler are never to be used.

Since async voids are fire and forget types and cause a lot of conundrum.

What you should use is a Task or a Task<T> instead.

I would suggest you read this awesome guide by MSDN on Async and Await Best Practices where they have explained everything so well if you read it.

Now jumping to your code you need to have the following changes in your code so that this issue does not happen

execution returns at var response = await client.PostAsync(base_url + "api_delivery_details", formcontent).ConfigureAwait(false); to the calling method getaddress() but executes the remaining portion later.so getting null result. How to execute all from first time?

Change your code like below:

 public async Task Get_branch_products()
    {
        RestClient restClient = new RestClient();            
        await GetAddresses();  //this is the calling method

        long delivery_fee1 = long.Parse(delivery_fee);
        GrandTotal = Total + (Total * Tax) / 100 + delivery_fee1 ;            
        OnPropertyChanged("GrandTotal");
        tax_amt = (Total * Tax) / 100;
        OnPropertyChanged("tax_amt");
    }


public async Task GetAddresses()
    {
        ind_vis = true;
        OnPropertyChanged("ind_vis");             
        int user_id = (int)App.Current.Properties["user_id"];
        RestClient restClient = new RestClient();
        var result = await restClient.Get_address(user_id);  //calling restAPI method

        if (result.status == "success")
        {
            ind_vis = false;
            OnPropertyChanged("ind_vis");


public async Task<Address> Get_address(int user_id)
    {
        var formcontent = new FormUrlEncodedContent(new[]
        {
           new KeyValuePair<string,string>("user_id",user_id.ToString())
        });
  //returns from here// var response = await client.PostAsync(base_url + "api_delivery_details", formcontent).ConfigureAwait(false); 
  //executes later// var result = await response.Content.ReadAsStringAsync();
        var Items = JsonConvert.DeserializeObject<Address>(result);
        return Items;
    }

Once this is done your code will wait for the GetAddresses method to get you the data and it will then move further.

Upvotes: 2

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