Added new kb article htmlchart-bind-dynamic-expando-list (#676)

Co-authored-by: KB Bot <[email protected]>

Author: github-actions[bot]

knowledge-base/htmlchart-bind-dynamic-expando-list.md

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+---
+title: Using Dynamic ExpandoObject as DataSource in RadHtmlChart
+description: Learn how to bind a dynamic ExpandoObject list to the DataSource of a RadHtmlChart in ASP.NET AJAX applications.
+type: how-to
+page_title: Binding Dynamic Expando List to RadHtmlChart DataSource in ASP.NET AJAX
+slug: htmlchart-bind-dynamic-expando-list
+tags: radhtmlchart, asp.net ajax, datasource, databind, expandoobject, datatable
+res_type: kb
+ticketid: 1684733
+---
+
+## Environment
+
+<table>
+<tbody>
+<tr>
+<td>Product</td>
+<td>RadHtmlChart for ASP.NET AJAX</td>
+</tr>
+<tr>
+<td>Version</td>
+<td>All</td>
+</tr>
+</tbody>
+</table>
+
+## Description
+
+I have created a dynamic "expando" object list and assigned it to the DataSource of a RadHtmlChart. No error occurs, but the HTMLChart remains empty. In CodeLens, I see the DataSource is available on the RadHTMLChart. Is this type of DataSource supported?
+
+
+This knowledge base article also answers the following questions:
+
+- How to bind a RadHtmlChart to a dynamic data source in ASP.NET AJAX?
+- Can I use an ExpandoObject as a DataSource for RadHtmlChart?
+- How to convert an ExpandoObject list to a DataTable for RadHtmlChart binding?
+
+## Solution
+
+The `ExpandoObject` is not directly supported as a data source for the RadHtmlChart due to the dynamic creation of its properties. However, you can convert an `ExpandoObject` list to a `DataTable`, which is a supported data source for the RadHtmlChart. Follow these steps to convert and bind the data:
+
+1. Convert the `ExpandoObject` list to a `DataTable`.
+
+2. Bind the `DataTable` to the RadHtmlChart.
+
+Here's the implementation:
+
+````C#
+protected void Page_Load(object sender, EventArgs e)
+{
+    if (!IsPostBack)
+    {
+        RadHtmlChart1.DataSource = GetDataSource();
+        RadHtmlChart1.DataBind();
+    }
+}
+
+private DataTable GetDataSource()
+{
+    List<ExpandoObject> dataSource = GetExpandoObjectData();
+    DataTable dataTable = ExpandoListToDataTable(dataSource);
+
+    return dataTable;
+}
+
+private DataTable ExpandoListToDataTable(List<ExpandoObject> list)
+{
+    DataTable dataTable = new DataTable();
+
+    if (list == null || list.Count == 0) return dataTable;
+
+    // Use the first item to define the columns
+    IDictionary<string, object> firstRow = list[0];
+    foreach (string key in firstRow.Keys)
+    {
+        dataTable.Columns.Add(key, firstRow[key].GetType() ?? typeof(object));
+    }
+
+    // Populate the rows
+    foreach (ExpandoObject item in list)
+    {
+        IDictionary<string, object> dict = item;
+        DataRow row = dataTable.NewRow();
+        foreach (string key in dict.Keys)
+        {
+            row[key] = dict[key] ?? DBNull.Value;
+        }
+        dataTable.Rows.Add(row);
+    }
+
+    return dataTable;
+}
+
+private List<ExpandoObject> GetExpandoObjectData()
+{
+    // Example data creation using ExpandoObject
+    dynamic row1 = new ExpandoObject();
+    row1.X_Axis_Categories = "Label 1";
+    row1.First_Series_Values = 1;
+    row1.Second_Series_Values = 5;
+
+    dynamic row2 = new ExpandoObject();
+    row2.X_Axis_Categories = "Label 2";
+    row2.First_Series_Values = 10;
+    row2.Second_Series_Values = 15;
+
+    return new List<ExpandoObject> { row1, row2 };
+}
+````
+
+3. Ensure your RadHtmlChart markup is set up to use the columns from your DataTable as data fields:
+
+````ASP.NET
+<telerik:RadHtmlChart runat="server" ID="RadHtmlChart1" Height="300px">
+    <PlotArea>
+        <Series>
+            <telerik:LineSeries DataFieldY="First_Series_Values" Name="first series"></telerik:LineSeries>
+            <telerik:LineSeries DataFieldY="Second_Series_Values" Name="second series"></telerik:LineSeries>
+        </Series>
+        <XAxis DataLabelsField="X_Axis_Categories"></XAxis>
+    </PlotArea>
+</telerik:RadHtmlChart>
+````
+
+## See Also
+
+- [Data Binding Overview for RadHtmlChart](https://www.telerik.com/products/aspnet-ajax/documentation/controls/htmlchart/data-binding/overview#data-binding-overview)
+- [DataTable Class in .NET](https://docs.microsoft.com/en-us/dotnet/api/system.data.datatable?view=netframework-4.8)