Esempio operazioni condizionali dell'API Web (C#)
Data di pubblicazione: gennaio 2017
Si applica a: Dynamics 365 (online), Dynamics 365 (on-premises), Dynamics CRM 2016, Dynamics CRM Online
In questo esempio viene illustrato come eseguire le operazioni condizionali utilizzando l'API Web Dynamics 365 e C#.
Nota
In questo esempio vengono implementate le operazioni e l'output della console Dynamics 365 spiegati in Esempio operazioni condizionali dell'API Web e vengono utilizzati i costrutti C# comuni descritti in Esempi di API Web (C#).
In questo argomento
Prerequisiti
Eseguire l'esempio
Esempio di codice
Prerequisiti
I prerequisiti per tutti gli esempi C# API Web Dynamics 365 sono spiegati nella sezione Prerequisiti dell'argomento padre Esempi di API Web (C#).
Eseguire l'esempio
Per eseguire l'esempio:
Passa a Esempio di operazioni condizionali API Web Microsoft CRM (C#), scarica il file Microsoft CRM Web API Conditional Operations Sample (CS).zip ed estrai il contenuto del file in una cartella nel computer. La cartella estratta deve contenere i file seguenti:
File
Descrizione
Program.cs
Contiene il codice sorgente per questo esempio.
App.config
Il file di configurazione dell'applicazione, contenente le informazioni segnaposto di connessione del server Dynamics 365.
ConditionalOperations.sln
ConditionalOperations.csproj
Packages.config
AssemblyInfo.csLa soluzione Visual Studio, il progetto, il pacchetto NuGet e i file di informazioni dell'assembly per questo esempio.
Faie doppio clic sul file ConditionalOperations.sln per aprire la soluzione in Visual Studio.
Crea la soluzione (Compila > Compila soluzione). Vengono scaricati e aggiornati automaticamente tutti i pacchetti NuGet necessari.
Modifica il file App.Config nella soluzione per specificare la tua istanza del server Dynamics 365 in cui desideri eseguire questo esempio.
Esegui il progetto. Tutti i progetti di esempio sono configurati per l'esecuzione in modalità di debug per impostazione predefinita.
L'output del codice di esempio verrà visualizzato in una finestra della console.
Esempio di codice
Program.cs
using Microsoft.Crm.Sdk.Samples.HelperCode;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Net;
using System.Linq;
using System.Text;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;
namespace Microsoft.Crm.Sdk.Samples
{
/// <summary>
/// This program performs conditional operations using the ETag property during Web
/// API calls in Microsoft CRM or later.
/// </summary>
/// <remarks>
/// Etags can be used in the following general areas:
/// - Optimize state retrieval (conditional GETs).
/// - Control upsert operations, either by preventing create operations (update only)
/// or by preventing updates (create only).
/// - Ensure optimistic concurrency in delete or update operations.
///
/// Before building this application, you must first modify the following configuration
/// information in the app.config file:
/// - All deployments: Provide connection string service URL's for your organization.
/// - CRM (online): Replace the app settings with the correct values for your Azure
/// application registration.
/// See the provided app.config file for more information.
/// </remarks>
class ConditionalOperations
{
// Variables used in the sample
private HttpClient httpClient; // Client to CRM server communication
private JObject account; // Sample CRM entity instance
private string accountUri; // Sample instance absolute URI
private string queryOptions; // Select clause to filter the record retrievals
private string initialAcctETagVal; // The initial ETag value of the account created
private string updatedAcctETagVal; // The ETag value of the account after it is updated
/// <summary>
/// Primary method that demonstrates Microsoft CRM Web API
/// Conditional operations.
/// </summary>
public async Task RunAsync()
{
HttpRequestMessage request;
HttpResponseMessage response;
#region Conditional GET
Console.WriteLine("\n--Conditional GET section started--");
// Attempt to retrieve using conditional GET with current ETag value.
request = new HttpRequestMessage(HttpMethod.Get, accountUri + queryOptions);
// Retrieve only if it doesn't match previously retrieved version.
request.Headers.Add("If-None-Match", initialAcctETagVal);
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.NotModified) // 304; expected.
{
Console.WriteLine("Instance retrieved using ETag: {0}", initialAcctETagVal);
Console.WriteLine("Expected outcome: Entity was not modified so nothing was returned.");
}
else if (response.StatusCode == HttpStatusCode.OK) // 200; not expected
{
Console.WriteLine("Instance retrieved using ETag: {0}", initialAcctETagVal);
account = JsonConvert.DeserializeObject<JObject>(
await response.Content.ReadAsStringAsync());
Console.WriteLine(account.ToString(Formatting.Indented));
}
else
{
throw new CrmHttpResponseException(response.Content);
}
// Modify the account instance by updating telephone1
String accountPhoneUri = String.Format("{0}/{1}", accountUri, "telephone1");
JObject phoneProperty = new JObject();
phoneProperty.Add("value", "555-0001");
response = await SendAsJsonAsync(httpClient, HttpMethod.Put, accountPhoneUri,
phoneProperty);
if (response.StatusCode == HttpStatusCode.NoContent)
{
Console.WriteLine("\nAccount telephone number updated.");
}
else
{
throw new CrmHttpResponseException(response.Content);
}
// Reattempt conditional GET with original ETag value.
request = new HttpRequestMessage(HttpMethod.Get, accountUri + queryOptions);
request.Headers.Add("If-None-Match", initialAcctETagVal);
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.OK) //200; expected
{
Console.WriteLine("Instance retrieved using ETag: {0}", initialAcctETagVal);
}
else if (response.StatusCode == HttpStatusCode.NotModified) // 304; not expected
{
Console.WriteLine("Unexpected status code: '{0}'.", (int)response.StatusCode);
}
else
{ throw new CrmHttpResponseException(response.Content); }
// Retrieve and output current account state.
account = JsonConvert.DeserializeObject<JObject>(
await response.Content.ReadAsStringAsync());
updatedAcctETagVal = account["@odata.etag"].ToString(); // Capture updated ETag
Console.WriteLine(account.ToString(Formatting.Indented));
#endregion Conditional GET
#region Optimistic concurrency on delete and update
Console.WriteLine("\n--Optimistic concurrency section started--");
// Attempt to delete original account (if matches original ETag value).
request = new HttpRequestMessage(HttpMethod.Delete, accountUri);
request.Headers.Add("If-Match", initialAcctETagVal); // If you replace "initialAcctETagVal" with "updatedAcctETagVal",
// delete will succeed.
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.PreconditionFailed) // 412; Precondition failed error expected
{
Console.WriteLine("Expected Error: The version of the existing record doesn't match the property provided.");
Console.WriteLine("\tAccount not deleted using ETag '{0}', status code: '{1}'.",
initialAcctETagVal, (int)response.StatusCode);
}
else if (response.IsSuccessStatusCode) // 200-299; not expected
{
Console.WriteLine("Account deleted!");
}
else
{
throw new CrmHttpResponseException(response.Content);
}
//Attempt to update account (if matches original ETag value).
JObject accountUpdate = new JObject();
accountUpdate.Add("telephone1", "555-0002");
accountUpdate.Add("revenue", 6000000);
request = new HttpRequestMessage(new HttpMethod("PATCH"), accountUri);
request.Content = new StringContent(accountUpdate.ToString(),
Encoding.UTF8, "application/json");
request.Headers.Add("If-Match", initialAcctETagVal);
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.PreconditionFailed) // 412; //Precondition failed error expected
{
Console.WriteLine("Expected Error: The version of the existing record doesn't match the property provided.");
Console.WriteLine("\tAccount not updated using ETag '{0}', status code: '{1}'.",
initialAcctETagVal, (int)response.StatusCode);
}
else if (response.StatusCode == HttpStatusCode.NoContent) // 204; not expected
{
Console.WriteLine("Account updated using ETag: {0}, status code: '{1}'.",
initialAcctETagVal, (int)response.StatusCode);
}
else
{
throw new CrmHttpResponseException(response.Content);
}
// Reattempt update if matches current ETag value.
accountUpdate["telephone1"] = "555-0003";
request = new HttpRequestMessage(new HttpMethod("PATCH"), accountUri);
request.Content = new StringContent(accountUpdate.ToString(),
Encoding.UTF8, "application/json");
request.Headers.Add("If-Match", updatedAcctETagVal);
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.NoContent) // 204; expected
{
Console.WriteLine("\nAccount successfully updated using ETag: {0}, status code: '{1}'.",
updatedAcctETagVal, (int)response.StatusCode);
}
else if (response.StatusCode == HttpStatusCode.PreconditionFailed) // 412; not expected
{
Console.WriteLine("Unexpected status code: '{0}'", (int)response.StatusCode);
}
else
{
throw new CrmHttpResponseException(response.Content);
}
// Retrieve and output current account state.
account = GetCurrentRecord(accountUri, queryOptions);
updatedAcctETagVal = account["@odata.etag"].ToString(); //Capture updated ETag
Console.WriteLine(account.ToString(Formatting.Indented));
#endregion Optimistic concurrency on delete and update
#region Controlling upsert operations
Console.WriteLine("\n--Controlling upsert operations section started--");
//Attempt to insert without update some properties for this account
accountUpdate = new JObject();
accountUpdate.Add("telephone1", "555-0004");
accountUpdate.Add("revenue", 7500000);
request = new HttpRequestMessage(new HttpMethod("PATCH"), accountUri);
request.Content = new StringContent(accountUpdate.ToString(),
Encoding.UTF8, "application/json");
//Perform operation only if matching resource does not exist.
request.Headers.Add("If-None-Match", "*");
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.PreconditionFailed) // 412; expected
{
Console.WriteLine("Expected Error: A record with matching key values already exists.");
Console.WriteLine("\tAccount not updated using ETag '{0}, status code: '{1}'.",
initialAcctETagVal, (int)response.StatusCode);
}
else if (response.StatusCode == HttpStatusCode.NoContent) // 204; unexpected
{
Console.WriteLine("Account updated using If-None-Match '*'");
}
else
{
throw new CrmHttpResponseException(response.Content);
}
//Attempt to perform same update without creation.
accountUpdate["telephone1"] = "555-0005";
request = new HttpRequestMessage(new HttpMethod("PATCH"), accountUri);
request.Content = new StringContent(accountUpdate.ToString(),
Encoding.UTF8, "application/json");
//Perform operation only if matching resource exists.
request.Headers.Add("If-Match", "*");
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.NoContent) // 204; expected
{
Console.WriteLine("Account updated using If-Match '*'");
}
else if (response.StatusCode == HttpStatusCode.PreconditionFailed) // 412; not expected
{
Console.WriteLine("Account not updated using If-Match '*', status code: '{0}'.",
(int)response.StatusCode);
}
else
{ throw new CrmHttpResponseException(response.Content); }
//Retrieve and output current account state.
account = GetCurrentRecord(accountUri, queryOptions);
Console.WriteLine(account.ToString(Formatting.Indented));
// Delete the account record
HttpResponseMessage deleteResponse;
deleteResponse = httpClient.DeleteAsync(accountUri).Result;
if (deleteResponse.IsSuccessStatusCode) // 200-299
{
Console.WriteLine("\nAccount was deleted.");
}
else if (deleteResponse.StatusCode == HttpStatusCode.NotFound)
// 404; entity record may have been deleted by another user.
{
Console.WriteLine("Account could not be found.");
}
else // Failed to delete
{
// Throw last failure.
throw new CrmHttpResponseException(response.Content);
}
// Attempt to update it
accountUpdate["telephone1"] = "555-0006";
request = new HttpRequestMessage(new HttpMethod("PATCH"), accountUri);
request.Content = new StringContent(accountUpdate.ToString(),
Encoding.UTF8, "application/json");
// Perform operation only if matching resource exists.
request.Headers.Add("If-Match", "*");
response = await httpClient.SendAsync(request);
if (response.StatusCode == HttpStatusCode.PreconditionFailed ||
response.StatusCode == HttpStatusCode.NotFound) // 412 or 404; expected
{
Console.WriteLine("Expected Error: Account with Id = {0} does not exist.", account["accountid"]);
Console.WriteLine("Account not updated because it does not exist, status code: '{0}'.",
(int)response.StatusCode);
}
else if (response.StatusCode == HttpStatusCode.NoContent) // 204; not expected
{
Console.WriteLine("Account upserted using If-Match '*'");
}
else
{
throw new CrmHttpResponseException(response.Content);
}
#endregion Controlling upsert operations
}
/// <summary> Main method for the ConditionalOperations project. </summary>
/// <param name="args">
/// Command line arguments, first is the optional connection string name.
/// </param>
static void Main(string[] args)
{
ConditionalOperations app = new ConditionalOperations();
try
{
Console.WriteLine("-- Sample started --");
app.ConnectToCRM(args); // Read configuration file and connect to the specified CRM instance.
app.CreateRequiredRecords(); // Create sample records for the sample
Task.WaitAll(Task.Run(async () => await app.RunAsync()));
}
catch (System.Exception ex)
{ DisplayException(ex); }
finally
{
if (app.httpClient != null)
{
app.httpClient.Dispose();
}
Console.WriteLine("\nPress <Enter> to exit the program.");
Console.ReadLine();
}
}
/// <summary>
/// Obtains the connection information from the application's configuration file,
/// and uses this info to connect to the specified CRM service.
/// </summary>
/// <param name="args">Command line arguments</param>
private void ConnectToCRM(String[] cmdargs)
{
// Create a helper object to read app.config for service URL and application
// registration settings.
Configuration config = null;
if (cmdargs.Length > 0)
config = new FileConfiguration(cmdargs[0]);
else
config = new FileConfiguration(null);
// Create a helper object to authenticate the user with this connection info.
Authentication auth = new Authentication(config);
// Next use a HttpClient object to connect to specified CRM Web service.
httpClient = new HttpClient(auth.ClientHandler, true);
// Define the Web API base address, the max period of execute time, the
// default OData version, and the default response payload format.
httpClient.BaseAddress = new Uri(config.ServiceUrl + "api/data/v8.1/");
httpClient.Timeout = new TimeSpan(0, 2, 0);
httpClient.DefaultRequestHeaders.Add("OData-MaxVersion", "4.0");
httpClient.DefaultRequestHeaders.Add("OData-Version", "4.0");
httpClient.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
}
/// <summary> Creates the CRM entity instance used by this sample. </summary>
private void CreateRequiredRecords()
{
// Create a CRM account record.
Console.WriteLine("\nCreate sample data");
account = new JObject();
account.Add("name", "Contoso Ltd");
account.Add("telephone1", "555-0000"); //Phone number value will increment with each update attempt
account.Add("revenue", 5000000);
account.Add("description", "Parent company of Contoso Pharmaceuticals, etc.");
HttpResponseMessage response = SendAsJsonAsync(httpClient, HttpMethod.Post,
"accounts", account).Result;
if (response.StatusCode == HttpStatusCode.NoContent)
{
accountUri = response.Headers.GetValues("OData-EntityId").FirstOrDefault();
}
else
{
throw new CrmHttpResponseException(response.Content);
}
// Retrieve the account record you created.
queryOptions = "?$select=name,revenue,telephone1,description";
account = GetCurrentRecord(accountUri, queryOptions);
Console.WriteLine("Account entity created:");
Console.WriteLine(account.ToString(Formatting.Indented));
initialAcctETagVal = account["@odata.etag"].ToString();
}
/// <summary>
/// Returns the current state of the specified entity, using the specified query criteria.
/// </summary>
/// <param name="entityUri">Relative URI of the entity instance to retrieve</param>
/// <param name="selectCriteria">Query selection, filtering, expansion</param>
/// <returns>JObject containing entity's specified properties; otherwise null if not exists.
/// </returns>
private JObject GetCurrentRecord(string entityUri, string queryOptions)
{
JObject entity = null;
if (String.IsNullOrEmpty(entityUri))
{ throw new ArgumentNullException(); }
HttpResponseMessage response = httpClient.GetAsync(entityUri + queryOptions).Result;
if (response.StatusCode == HttpStatusCode.OK) //200
{
string body = response.Content.ReadAsStringAsync().Result;
entity = JsonConvert.DeserializeObject<JObject>(body);
}
else if (response.StatusCode == HttpStatusCode.NotFound) //404
{ return null; }
else
{ throw new CrmHttpResponseException(response.Content); }
return entity;
}
/// <summary> Sends an HTTP message containing a JSON payload to the target URL. </summary>
/// <typeparam name="T">Type of the data to send in the message content (payload)</typeparam>
/// <param name="client">A preconfigured HTTP client</param>
/// <param name="method">The HTTP method to invoke</param>
/// <param name="requestUri">The relative URL of the message request</param>
/// <param name="value">The data to send in the payload. The data will be converted to a
/// serialized JSON payload. </param>
/// <returns>An HTTP response message</returns>
private async Task<HttpResponseMessage> SendAsJsonAsync<T>(HttpClient client,
HttpMethod method, string requestUri, T value)
{
string content;
if (value.GetType().Name.Equals("JObject"))
{ content = value.ToString(); }
else
{
content = JsonConvert.SerializeObject(value, new JsonSerializerSettings()
{ DefaultValueHandling = DefaultValueHandling.Ignore });
}
HttpRequestMessage request = new HttpRequestMessage(method, requestUri);
request.Content = new StringContent(content);
request.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json");
return await client.SendAsync(request);
}
/// <summary> Displays exception information to the console. </summary>
/// <param name="ex">The exception to output</param>
private static void DisplayException(Exception ex)
{
Console.WriteLine("The application terminated with an error.");
Console.WriteLine(ex.Message);
while (ex.InnerException != null)
{
Console.WriteLine("\t* {0}", ex.InnerException.Message);
ex = ex.InnerException;
}
}
}
}
Vedere anche
Utilizzare l'API Web di Microsoft Dynamics 365
Eseguire operazioni condizionali tramite l'API Web
Esempi di API Web
Esempio operazioni condizionali dell'API Web
Esempio di operazioni condizionali API Web (JavaScript lato client)
Esempio di operazioni di base dell'API Web (C#)
Esempio di dati di query API Web (C#)
Esempio di azioni e funzioni API Web (C#)
Microsoft Dynamics 365
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