Question 86166 in ASP.NET Question posted in
The official documentation can be found here.

the datasource for gridview Gridview1 didn't have any properties or attributes from which to generate columns. Ensure that your datasource has content – Asp.net

This is the error I’m getting. The data is being retrieved through WebAPI, but due to a gridview setting, it is not displaying the retrieved data.

      protected void Page_Load(object sender, EventArgs e)
      {
          try
          {
              var webRequest = (HttpWebRequest)WebRequest.Create("https://localhost:44342/api/author");
              var webResponse = (HttpWebResponse)webRequest.GetResponse();
              if ((webResponse.StatusCode == HttpStatusCode.OK) && (webResponse.ContentLength > 0))
              {
                  var reader = new StreamReader(webResponse.GetResponseStream());
                  string s = reader.ReadToEnd();
                  var arr = JsonConvert.DeserializeObject<JArray>(s);
                  //Console.WriteLine(arr);
                  GridView1.DataSource = arr;
                  GridView1.DataBind();
              }
              else
              {
                  MessageBox.Show(string.Format("Status code == {0}", webResponse.StatusCode));
              }
          }
          catch (Exception ex)
          {
              MessageBox.Show(ex.Message);
          }

webform.aspx file gridview code

<asp:GridView ID="GridView1" Class="mygridview" runat="server" OnSelectedIndexChanged="GridView1_SelectedIndexChanged" BorderStyle="Solid" CellPadding="10"  >
                             <Columns>
                                <asp:BoundField DataField="author_id" HeaderText="AuthorID" />
                                <asp:BoundField DataField="author_name" HeaderText="firstName" />
                            </Columns>
                         </asp:GridView>

Controller code:

public IHttpActionResult getauthor()
        {
            librariaEntities lb = new librariaEntities();
            var results = lb.Authors.ToList();
            return Ok(results);
 
        }
Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0 
      protected void Page_Load(object sender, EventArgs e)
    {
      try
        {
            var webRequest = (HttpWebRequest)WebRequest.Create("https://localhost:44342/api/author");
            var webResponse = (HttpWebResponse)webRequest.GetResponse();
            if ((webResponse.StatusCode == HttpStatusCode.OK) && (webResponse.ContentLength > 0))
            {
                var reader = new StreamReader(webResponse.GetResponseStream());
                string s = reader.ReadToEnd();
                GridView1.DataSource = (new JavaScriptSerializer()).Deserialize<List<Author>>(s);
                GridView1.DataBind();
            }
            else
            {
                MessageBox.Show(string.Format("Status code == {0}", webResponse.StatusCode));
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    Deseriaziled the returned value from the web API as a list (or array) of Author objects and it worked eventually.


  2. 0

    Okay, this looks pretty simple.

    The GridView control needs to bind to a list of objects. You’re doing this with the JArray. So far, so good.

    But the GridView doesn’t know how to get properties called "author_id" and "author_name" from the objects in the JArray. There are no such strongly-typed properties in those objects.

    Can you deserialize your return value from the web API as a list (or array) of Author objects?

    Incidentally, you’re working with ASP.Net WebForms, not MVC.

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search