using System.IO;

/// <summary>

/// WebApi返回图片

/// </summary>

public HttpResponseMessage GetQrCode()

{

    var imgPath = @"D:\ITdosCom\Images\itdos.jpg";

    //从图片中读取byte

    var imgByte = File.ReadAllBytes(imgPath);

    //从图片中读取流

    var imgStream = new MemoryStream(File.ReadAllBytes(imgPath));

    var resp = new HttpResponseMessage(HttpStatusCode.OK)

    {

        Content = new ByteArrayContent(imgByte)

        //或者

        //Content = new StreamContent(stream)

    };

    resp.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpg");

    return resp;

}

/// <summary>

/// WebApi返回json数据

/// </summary>

public HttpResponseMessage GetQrCode()

{

    var jsonStr = "{\"IsSuccess\":true,\"Data\":\"www.itdos.com\"}";

    var result = new HttpResponseMessage(HttpStatusCode.OK)

                    {

                        Content = new StringContent(jsonStr, Encoding.UTF8, "text/json")

                    };

    return result;

}

/// <summary>

/// WebApi返回字符串

/// </summary>

public HttpResponseMessage GetQrCode()

{

    var str = "IT大师www.itdos.com";

    var result = new HttpResponseMessage(HttpStatusCode.OK)

                    {

                        Content = new StringContent(str, Encoding.UTF8, "text/plain")

                    };

    return result;

}