How to covert Json result into string in Blazor WebAssembly? - http-get

Question

I want to convert the result into a string and pass it to the navigation path, but I couldn't do it, please help me.
HttpGet Controller
[HttpGet]
[Route("UserId")]
public async Task<ActionResult<ApplicationUser>> GetUserId(string Username)
{
var user = await userManager.FindByNameAsync(Username);
if (user == null)
return StatusCode(StatusCodes.Status500InternalServerError, new Response { Status = "Error", Message = "User not exist" });
var result = await userManager.GetUserIdAsync(user);
return new JsonResult(result);
}
Controller return result
"85e39a3e-8101-4166-9193-5e41bec1a7ce"
Function
private async Task Login()
{
var user = new userName { Username = Username };
var loginUser = new LoginDb { Username = Username, Password = Password };
if (Username == null || Password == null)
{
toastService.ShowWarning("Please enter Username and Password");
}
else
{
user = await Http.GetFromJsonAsync<userName>("Authentication/UserId?Username=" + Username);
if (user != null)
{
string Id = System.Text.Json.JsonSerializer.Serialize(user);
var result = await Http.PostAsJsonAsync("Authentication/login", loginUser);
if (result.IsSuccessStatusCode)
{
NavigationManager.NavigateTo("/profile/" + Id);
toastService.ShowSuccess("Login successful");
}
else
{
toastService.ShowError("Username or Password is wrong");
}
}
else
{
NavigationManager.NavigateTo("/login");
}
}
}

Answer 1

OK, I can see a few problems.
On the Server:
[HttpGet]
[Route("UserId")]
public async Task<ActionResult<ApplicationUser>> GetUserId(string Username) // A
{
var user = await userManager.FindByNameAsync(Username);
if (user == null) // B
return StatusCode(StatusCodes.Status500InternalServerError, new Response { Status = "Error", Message = "User not exist" });
var result = await userManager.GetUserIdAsync(user);
return new JsonResult(result);
}
First, your return type here is Task<ActionResult<ApplicationUser>> . ApplicationUser is tied to the backend Identity library, you can't and shouldn't use it for a DTO.
And you don't, in the end you have return new JsonResult(result); which is OK when you change the return type to just Task<ActionResult>.
On the client:
//user = await Http.GetFromJsonAsync<userName>("Authentication/UserId?Username=" + Username);
var userId = await Http.GetFromJsonAsync<string>("Authentication/UserId?Username=" + Username);
The endpoint returns a simple string. Json does not know about 'UserName' or anything else.
//string Id = System.Text.Json.JsonSerializer.Serialize(user); -- use UserId
You are serializing the Id (again) here, making it almost certainly invalid for an URL. So just skip that.