System.InvalidCastException: Specified cast is not valid.
Bonjour à tous,
Je suis actuellement en train de faire une API pour accéder à une base de données MySQL (à titre d’exercice) avec une appli android. Je rencontre quelques problèmes (sinon je ne serai pas là). J'utilise Visual Studio.
L'erreur généré lors du deboggage est System.InvalidCastException: Specified cast is not valid .
Voici le code :
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| using System;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using System.Json;
using System.Net;
using System.Threading.Tasks;
using System.IO;
using Newtonsoft.Json;
using Microsoft.CSharp;
namespace API_Test
{
[Activity(Label = "API_Test", MainLauncher = true, Icon = "@drawable/icon")]
public class MainActivity : Activity
{
private Button button;
private EditText reponseAPI;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
// Get the latitude/longitude EditBox and button resources:
button = FindViewById<Button>(Resource.Id.btnCall);
// When the user clicks the button ...
button.Click += async (sender, e) => {
// Get the latitude and longitude entered by the user and create a query.
string url = "http://192.168.X.XX/API_xxxx.php?xxx";
// Fetch the weather information asynchronously,
// parse the results, then update the screen:
JsonValue json = await FetchWeatherAsync(url);
//ParseAndDisplay (json);
};
}
// Gets weather data from the passed URL.
private async Task<JsonValue> FetchWeatherAsync(string url)
{
// Create an HTTP web request using the URL:
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(new Uri(url));
request.ContentType = "application/json";
request.Method = "GET";
// Send the request to the server and wait for the response:
using (WebResponse response = await request.GetResponseAsync())
{
// Get a stream representation of the HTTP web response:
using (Stream stream = response.GetResponseStream())
{
// Use this stream to build a JSON document object:
JsonValue jsonDoc = await Task.Run(() => JsonObject.Load(stream));
Console.Out.WriteLine("Test3: {0}", jsonDoc.ToString());
// Return the JSON document:
return jsonDoc;
}
}
}
private void ParseAndDisplay(JsonValue json)
{
reponseAPI = FindViewById<EditText>(Resource.Id.reponseAPI);
//dynamic Toto = JsonObject.Parse(json);
//string lolo = Toto.id;
//reponseAPI.Text = lolo;
//var m = JsonConvert.DeserializeObject<dynamic>(json);
//Console.Out.WriteLine("oooo");
//string name = m.id;
}
}
} |
Après avoir cliquer sur le bouton "call" le mode débogue signale:
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| 08-22 12:25:30.250 D/Mono ( 5720): Image addref System.Json[0x9d3c3e60] -> System.Json.dll[0x9c1dba00]: 1
08-22 12:25:30.250 D/Mono ( 5720): Assembly System.Json[0x9d3c3e60] added to domain RootDomain, ref_count=1
08-22 12:25:30.250 D/Mono ( 5720): AOT module 'System.Json.dll.so' not found: dlopen failed: library "/data/app/API_Test.API_Test-1/lib/x86/libaot-System.Json.dll.so" not found
08-22 12:25:30.251 D/Mono ( 5720): AOT module '/Users/builder/data/lanes/3540/1cf254db/source/monodroid/builds/install/mono-x86/lib/mono/aot-cache/x86/System.Json.dll.so' not found: dlopen failed: library "/data/app/API_Test.API_Test-1/lib/x86/libaot-System.Json.dll.so" not found
08-22 12:25:30.251 D/Mono ( 5720): Config attempting to parse: 'System.Json.dll.config'.
08-22 12:25:30.251 D/Mono ( 5720): Config attempting to parse: '/Users/builder/data/lanes/3540/1cf254db/source/monodroid/builds/install/mono-x86/etc/mono/assemblies/System.Json/System.Json.config'.
08-22 12:25:30.251 D/Mono ( 5720): Assembly Ref addref API_Test[0xad97bbe0] -> System.Json[0x9d3c3e60]: 2
08-22 12:25:30.251 D/Mono ( 5720): Assembly Ref addref System.Json[0x9d3c3e60] -> mscorlib[0xad97bb80]: 14
Loaded assembly: System.Json.dll
08-22 12:25:30.268 D/Mono ( 5720): Assembly Ref addref API_Test[0xad97bbe0] -> System[0xb4099cc0]: 3
08-22 12:25:30.328 D/Mono ( 5720): Assembly Ref addref Mono.Android[0xb4099e40] -> System[0xb4099cc0]: 4
08-22 12:25:30.359 D/Mono ( 5720): DllImport searching in: '__Internal' ('(null)').
08-22 12:25:30.359 D/Mono ( 5720): Searching for 'java_interop_jnienv_call_int_method'.
08-22 12:25:30.359 D/Mono ( 5720): Probing 'java_interop_jnienv_call_int_method'.
08-22 12:25:30.359 D/Mono ( 5720): Found as 'java_interop_jnienv_call_int_method'.
08-22 12:25:30.364 D/Mono ( 5720): DllImport searching in: '__Internal' ('(null)').
08-22 12:25:30.364 D/Mono ( 5720): Searching for 'java_interop_jnienv_get_static_field_id'.
08-22 12:25:30.364 D/Mono ( 5720): Probing 'java_interop_jnienv_get_static_field_id'.
08-22 12:25:30.364 D/Mono ( 5720): Found as 'java_interop_jnienv_get_static_field_id'.
08-22 12:25:30.365 D/Mono ( 5720): DllImport searching in: '__Internal' ('(null)').
08-22 12:25:30.365 D/Mono ( 5720): Searching for 'java_interop_jnienv_get_static_object_field'.
08-22 12:25:30.365 D/Mono ( 5720): Probing 'java_interop_jnienv_get_static_object_field'.
08-22 12:25:30.365 D/Mono ( 5720): Found as 'java_interop_jnienv_get_static_object_field'.
08-22 12:25:30.367 D/Mono ( 5720): DllImport searching in: '__Internal' ('(null)').
08-22 12:25:30.367 D/Mono ( 5720): Searching for 'java_interop_jnienv_call_nonvirtual_boolean_method_a'.
08-22 12:25:30.367 D/Mono ( 5720): Probing 'java_interop_jnienv_call_nonvirtual_boolean_method_a'.
08-22 12:25:30.367 D/Mono ( 5720): Found as 'java_interop_jnienv_call_nonvirtual_boolean_method_a'.
Thread started: #2
Thread started: <Thread Pool> #3
Thread started: <Thread Pool> #4
08-22 12:25:30.427 D/Mono ( 5720): [0x9bb3f930] worker starting
Thread started: <Thread Pool> #5
08-22 12:25:30.512 D/Mono ( 5720): [0x9b97f930] worker starting
Thread started: <Thread Pool> #6
08-22 12:25:30.617 D/Mono ( 5720): [0x9bb3f930] hill climbing, change max number of threads 2
08-22 12:25:30.697 D/Mono ( 5720): Assembly Ref addref System.Json[0x9d3c3e60] -> System.Core[0x9d3c26c0]: 4
08-22 12:25:30.713 D/Mono ( 5720): Assembly Ref addref System.Json[0x9d3c3e60] -> System[0xb4099cc0]: 5
ducon: [{"id": "1", "nom": "Dylan", "prenom": "Bob"}]
08-22 12:25:30.766 D/Mono ( 5720): DllImport attempting to load: '/system/lib/liblog.so'.
08-22 12:25:30.767 D/Mono ( 5720): DllImport loaded library '/system/lib/liblog.so'.
08-22 12:25:30.767 D/Mono ( 5720): DllImport searching in: '/system/lib/liblog.so' ('/system/lib/liblog.so').
08-22 12:25:30.767 D/Mono ( 5720): Searching for '__android_log_print'.
08-22 12:25:30.767 D/Mono ( 5720): Probing '__android_log_print'.
08-22 12:25:30.767 D/Mono ( 5720): Found as '__android_log_print'.
08-22 13:55:08.394 I/mono-stdout( 3858): Test3: [{"id": "1", "nom": "Dylan", "prenom": "Bob"}]
08-22 12:25:30.779 D/Mono ( 5720): Assembly Ref addref API_Test[0xad97bbe0] -> Newtonsoft.Json[0xb077c640]: 2
08-22 12:25:30.779 D/Mono ( 5720): Assembly Ref addref Newtonsoft.Json[0xb077c640] -> System.Runtime[0xb077c700]: 3
Unhandled Exception:
System.InvalidCastException: Specified cast is not valid. |
Les posts de forum traitant de ce problème (stackoverflow) traite souvent d'une erreur de genre TypeValue ou de valeur nulle.
Merci de votre aide.
