.NET C# Adaptive Card Example | Simple Text and Image Block

using AdaptiveCards;
// ...

AdaptiveCard card = new AdaptiveCard(new AdaptiveSchemaVersion(1, 3));

card.Body.Add(new AdaptiveTextBlock() 
{
    Text = "Hello World",
    Size = AdaptiveTextSize.ExtraLarge
});

card.Body.Add(new AdaptiveImage() 
{
    Url = new Uri("http://adaptivecards.io/content/cats/1.png")
});

// serialize the card to JSON
string json = card.ToJson();

{
    "type": "AdaptiveCard",
    "$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
    "version": "1.3",
    "body": [
        {
            "type": "TextBlock",
            "text": "Hello World",
            "wrap": true,
            "size": "ExtraLarge"
        },
        {
            "type": "Image",
            "url": "http://adaptivecards.io/content/cats/1.png"
        }
    ]
}