Question

We have the DevExpress grid and in the OnCustomCallback event we need to assign a hidden field value=true. After we need to get the hidden field value to javascript?
We tried in following manner:

protected void dgUnReconcile_CustomCallback(object sender, ASPxGridViewCustomCallbackEventArgs e)
{
    ASPxGridView temp = ((DevExpress.Web.ASPxGridView.ASPxGridView)(sender));
    string gridInstancename = ((DevExpress.Web.ASPxGridView.ASPxGridView)(sender)).ClientInstanceName;

    if (gridInstancename.Equals("grid"))
    {
        List<Object> selected = dgUnReconcile.GetSelectedFieldValues(new[] { "Key" });
        if (selected.Count > 0)
        {    
                existingKey = true;//hidden field value
        }
    }
}

We need to access the hidden fields value through javascript

var ='<%# existingKey%>’;

It always shows empty value.

Answer 1

Try to use the JSProperties of the grid:

aspx:

<dxwgv:ASPxGridView ID="myGridView" ClientInstanceName="myGridView" runat="server">
</dxwgv:ASPxGridView>

sets the value in code-behind (C#):

myGridView.JSProperties["cpMyValue"] = "hello, world!";

gets the value on client (js):

alert(myGridView.cpMyValue);