The AWS Mobile SDK for Xamarin is now included in the AWS SDK for .NET. This guide references the archived version of the Mobile SDK for Xamarin.

Using the DynamoDB Service Level APIs

The Dynamo Service Level APIs allow you to create, update and delete tables. You can also perform typical create, read, update, and delete (CRUD) operations on items in a table using this API.

Create a DynamoDB Client

To create a DynamoDB client:

AmazonDynamoDBClient client = new AmazonDynamoDBClient(credentials,region);

CRUD Operations

Save an Item

To save an item to a DynamoDB table:

// Create a client
AmazonDynamoDBClient client = new AmazonDynamoDBClient(credentials,region);

// Define item attributes
Dictionary<string, AttributeValue> attributes = new Dictionary<string, AttributeValue>();

// Author is hash-key
attributes["Author"] = new AttributeValue { S = "Mark Twain" };
attributes["Title"] = new AttributeValue { S = "The Adventures of Tom Sawyer" };
attributes["PageCount"] = new AttributeValue { N = "275" };
attributes["Price"] = new AttributeValue{N = "10.00"};
attributes["Id"] = new AttributeValue{N="10"};
attributes["ISBN"] = new AttributeValue{S="111-1111111"};

// Create PutItem request
PutItemRequest request = new PutItemRequest
{
    TableName = "Books",
    Item = attributes
};

// Issue PutItem request
var response = await client.PutItemAsync(request);

Retrieve an Item

To retrieve an item:

// Create a client
AmazonDynamoDBClient client = new AmazonDynamoDBClient(credentials,region);

Dictionary<string, AttributeValue> key = new Dictionary<string, AttributeValue>
{
    { "Id", new AttributeValue { N = "10" } }
};

// Create GetItem request
GetItemRequest request = new GetItemRequest
{
    TableName = "Books",
    Key = key,
};

// Issue request
var result = await client.GetItemAsync(request);

// View response
Console.WriteLine("Item:");
Dictionary<string, AttributeValue> item = result.Item;
foreach (var keyValuePair in item)
{
    Console.WriteLine("Author := {0}", item["Author"]);
    Console.WriteLine("Title := {0}", item["Title"]);
    Console.WriteLine("Price:= {0}", item["Price"]);
    Console.WriteLine("PageCount := {0}", item["PageCount"]);
}

Update an Item

To update an item:

// Create a client
AmazonDynamoDBClient client = new AmazonDynamoDBClient(credentials,region);

Dictionary<string, AttributeValue> key = new Dictionary<string, AttributeValue>
{
    { "Id", new AttributeValue { N = "10" } }
};

// Define attribute updates
Dictionary<string, AttributeValueUpdate> updates = new Dictionary<string, AttributeValueUpdate>();
// Add a new string to the item's Genres SS attribute
updates["Genres"] = new AttributeValueUpdate()
{
    Action = AttributeAction.ADD,
    Value = new AttributeValue { SS = new List<string> { "Bildungsroman" } }
};

// Create UpdateItem request
UpdateItemRequest request = new UpdateItemRequest
{
    TableName = "Books",
    Key = key,
    AttributeUpdates = updates
};

// Issue request
var response = await client.UpdateItemAsync(request);

Delete an Item

To delete an item:

// Create a client
AmazonDynamoDBClient client = new AmazonDynamoDBClient(credentials,region);

Dictionary<string, AttributeValue> key = new Dictionary<string, AttributeValue>
{
  { "Id", new AttributeValue { N = "10" } }
};

// Create DeleteItem request
DeleteItemRequest request = new DeleteItemRequest
{
  TableName = "Books",
  Key = key
};

// Issue request
var response = await client.DeleteItemAsync(request);

Query and Scan

To query and retrieve all books whose author is “Mark Twain”:

public void Query(AWSCredentials credentials, RegionEndpoint region) {
  using(var client = new AmazonDynamoDBClient(credentials, region)) {
    var queryResponse = await client.QueryAsync(new QueryRequest() {
      TableName = "Books",
      IndexName = "Author-Title-index",
      KeyConditionExpression = "Author = :v_Id",
      ExpressionAttributeValues = new Dictionary < string, AttributeValue > {
        {
          ":v_Id", new AttributeValue {
            S = "Mark Twain"
          }
        }
      }
    });
    queryResponse.Items.ForEach((i) = > {
      Console.WriteLine(i["Title"].S);
    });

  }
}

The scan example code below returns all books in our table:

public void Scan(AWSCredentials credentials, RegionEndpoint region) {
      using(var client = new AmazonDynamoDBClient(credentials, region)) {
              var queryResponse = client.Scan(new ScanRequest() {
                      TableName = "Books"
              });
              queryResponse.Items.ForEach((i) = > {
                      Console.WriteLine(i["Title"].S);
              });
      }
}