Add missing SqlCommand_BeginExecuteReader sample

doc/samples/SqlCommand_BeginExecuteReader.cs

@@ -0,0 +1,100 @@
+// <Snippet1>
+using System;
+using Microsoft.Data.SqlClient;
+
+class Class1
+{
+    static void Main()
+    {
+        // This is a simple example that demonstrates the usage of the
+        // BeginExecuteReader functionality
+        // The WAITFOR statement simply adds enough time to prove the
+        // asynchronous nature of the command.
+        string commandText =
+            "WAITFOR DELAY '00:00:03';" +
+            "SELECT LastName, FirstName FROM Person.Contact " +
+            "WHERE LastName LIKE 'M%'";
+
+        RunCommandAsynchronously(commandText, GetConnectionString());
+
+        Console.WriteLine("Press ENTER to continue.");
+        Console.ReadLine();
+    }
+
+    private static void RunCommandAsynchronously(
+        string commandText, string connectionString)
+    {
+        // Given command text and connection string, asynchronously execute
+        // the specified command against the connection. For this example,
+        // the code displays an indicator as it is working, verifying the
+        // asynchronous behavior.
+        using (SqlConnection connection = new SqlConnection(connectionString))
+        {
+            try
+            {
+                SqlCommand command = new SqlCommand(commandText, connection);
+
+                connection.Open();
+                IAsyncResult result = command.BeginExecuteReader();
+
+                // Although it is not necessary, the following code
+                // displays a counter in the console window, indicating that
+                // the main thread is not blocked while awaiting the command
+                // results.
+                int count = 0;
+                while (!result.IsCompleted)
+                {
+                    count += 1;
+                    Console.WriteLine("Waiting ({0})", count);
+                    // Wait for 1/10 second, so the counter
+                    // does not consume all available resources
+                    // on the main thread.
+                    System.Threading.Thread.Sleep(100);
+                }
+
+                using (SqlDataReader reader = command.EndExecuteReader(result))
+                {
+                    DisplayResults(reader);
+                }
+            }
+            catch (SqlException ex)
+            {
+                Console.WriteLine("Error ({0}): {1}", ex.Number, ex.Message);
+            }
+            catch (InvalidOperationException ex)
+            {
+                Console.WriteLine("Error: {0}", ex.Message);
+            }
+            catch (Exception ex)
+            {
+                // You might want to pass these errors
+                // back out to the caller.
+                Console.WriteLine("Error: {0}", ex.Message);
+            }
+        }
+    }
+
+    private static void DisplayResults(SqlDataReader reader)
+    {
+        // Display the data within the reader.
+        while (reader.Read())
+        {
+            // Display all the columns. 
+            for (int i = 0; i < reader.FieldCount; i++)
+            {
+                Console.Write("{0}\t", reader.GetValue(i));
+            }
+            Console.WriteLine();
+        }
+    }
+
+    private static string GetConnectionString()
+    {
+        // To avoid storing the connection string in your code,            
+        // you can retrieve it from a configuration file. 
+
+        return "Data Source=(local);Integrated Security=true;" +
+            "Initial Catalog=AdventureWorks";
+    }
+}
+// </Snippet1>

doc/snippets/Microsoft.Data.SqlClient/SqlCommand.xml

@@ -1173,7 +1173,106 @@
           The following console application starts the process of retrieving a data reader asynchronously. While waiting for the results, this simple application sits in a loop, investigating the <see cref="P:System.IAsyncResult.IsCompleted" /> property value. As soon as the process has completed, the code retrieves the <see cref="T:Microsoft.Data.SqlClient.SqlDataReader" /> and displays its contents.
         </para>
         <!-- SqlCommand_BeginExecuteReader -->
-        <!-- SAMPLE MISSING -->
+        <code language="c#">
+          using System;
+          using Microsoft.Data.SqlClient;
+
+          class Class1
+          {
+              static void Main()
+              {
+                  // This is a simple example that demonstrates the usage of the
+                  // BeginExecuteReader functionality
+                  // The WAITFOR statement simply adds enough time to prove the
+                  // asynchronous nature of the command.
+                  string commandText =
+                      "WAITFOR DELAY '00:00:03';" +
+                      "SELECT LastName, FirstName FROM Person.Contact " +
+                      "WHERE LastName LIKE 'M%'";
+
+                  RunCommandAsynchronously(commandText, GetConnectionString());
+
+                  Console.WriteLine("Press ENTER to continue.");
+                  Console.ReadLine();
+              }
+
+              private static void RunCommandAsynchronously(
+                  string commandText, string connectionString)
+              {
+                  // Given command text and connection string, asynchronously execute
+                  // the specified command against the connection. For this example,
+                  // the code displays an indicator as it is working, verifying the
+                  // asynchronous behavior.
+                  using (SqlConnection connection = new SqlConnection(connectionString))
+                  {
+                      try
+                      {
+                          SqlCommand command = new SqlCommand(commandText, connection);
+
+                          connection.Open();
+                          IAsyncResult result = command.BeginExecuteReader();
+
+                          // Although it is not necessary, the following code
+                          // displays a counter in the console window, indicating that
+                          // the main thread is not blocked while awaiting the command
+                          // results.
+                          int count = 0;
+                          while (!result.IsCompleted)
+                          {
+                              count += 1;
+                              Console.WriteLine("Waiting ({0})", count);
+                              // Wait for 1/10 second, so the counter
+                              // does not consume all available resources
+                              // on the main thread.
+                              System.Threading.Thread.Sleep(100);
+                          }
+
+                          using (SqlDataReader reader = command.EndExecuteReader(result))
+                          {
+                              DisplayResults(reader);
+                          }
+                      }
+                      catch (SqlException ex)
+                      {
+                          Console.WriteLine("Error ({0}): {1}", ex.Number, ex.Message);
+                      }
+                      catch (InvalidOperationException ex)
+                      {
+                          Console.WriteLine("Error: {0}", ex.Message);
+                      }
+                      catch (Exception ex)
+                      {
+                          // You might want to pass these errors
+                          // back out to the caller.
+                          Console.WriteLine("Error: {0}", ex.Message);
+                      }
+                  }
+              }
+
+              private static void DisplayResults(SqlDataReader reader)
+              {
+                  // Display the data within the reader.
+                  while (reader.Read())
+                  {
+                      // Display all the columns. 
+                      for (int i = 0; i < reader.FieldCount; i++)
+                      {
+                          Console.Write("{0}\t", reader.GetValue(i));
+                      }
+                      Console.WriteLine();
+                  }
+              }
+
+              private static string GetConnectionString()
+              {
+                  // To avoid storing the connection string in your code,            
+                  // you can retrieve it from a configuration file. 
+
+                  return "Data Source=(local);Integrated Security=true;" +
+                      "Initial Catalog=AdventureWorks";
+              }
+          }
+        </code>
       </example>
       <exception cref="T:System.InvalidCastException">
         <list type="bullet">