Hello,

first of all, thank you for relelasing Dialog, it is what we are "simulating" by modal Window on any kind of heavy data editing app,again and again and again :) .

The problem is,
- when you put DropDownList in Dialog, using OnRead async task event, the UI is still "empty". => Iam fiddled with reassigning datasource, changing order of assigning source, nothing helped.
- same dropdownlist scenario inside window, working/displayed as expected.

Steps to reproduce:
1) click on then button to show window by -> async task
2) event OnRead of the dropdownlist is correctly called, data to the IEnumerable<model> is loaded
3) window appear, but DropDownList is empty
4) when you filter by typeing inside DropDownList, OnRead is called and model populated, but GUI is still empty

What doesnt worked:
- statechaned, reassign datasource, clear datasource, task delay

What partially worked:
- OnRead=> async Task changed to just: OnRead=> Task

Thanks for info what should be made done else.

Stripped sample:
<TelerikButton @onclick="@(() => ParamEd(4444, null))">open window or dialog</TelerikButton>
<TelerikWindow Modal="true" @bind-Visible="@ShowEditWindow" Draggable="true">
<WindowTitle>
<strong>@ShowEditWindowCaption</strong>
</WindowTitle>
<WindowContent>

<TelerikDropDownList @bind-Value="@CurrentEdit.ValTxt"
ScrollMode="@DropDownScrollMode.Virtual"
Data="@CurrentEdit.ComboSource"
OnRead="@ReadComboData"
ItemHeight="30"
TotalCount="@Paging.CNT"
PageSize="14"
PopupHeight="400px"
TextField="Nazev1"
ValueField="KeyVal"
Filterable="true"
FilterOperator="StringFilterOperator.Contains">
</TelerikDropDownList>
....
vs
<TelerikDialog @bind -Visible="@ShowEditWindow" Title="@ShowEditWindowCaption" CloseOnOverlayClick="false">
<DialogContent>
<TelerikDropDownList @bind-Value="@CurrentEdit.ValTxt"
ScrollMode="@DropDownScrollMode.Virtual"
Data="@CurrentEdit.ComboSource"
OnRead="@ReadComboData"
ItemHeight="30"
TotalCount="@Paging.CNT"
PageSize="14"
PopupHeight="400px"
TextField="Nazev1"
ValueField="KeyVal"
Filterable="true"
FilterOperator="StringFilterOperator.Contains">
</TelerikDropDownList>
....
@code{

[CascadingParameter]
public NotificationBase Notification { get; set; }
[CascadingParameter]
public DialogFactory Dialogs { get; set; }

//clicked on the button to show window/dialog:
async Task ParamEd(int xtyp, object it)
{
await Task.Delay(500);//await load captions... and THEN open window:
ShowEditWindowCaption = "window title";
ShowEditWindow = true;
}

async Task ReadComboData(DropDownListReadEventArgs e)
{
try
{
var r = await readDBDATA...
//CurrentEdit.ComboSource = new List<EdBase>();
//CurrentEdit.ComboSource = null;
//CurrentEdit.ComboSource = new IEnumerable<EdBase>(r);
//CurrentEdit.ComboSource = await ReadDBDATA
CurrentEdit.ComboSource = r;
Paging.CNT = p.Get<int>("CNT");

/*
//!! HOTFIX FROM ANOTHER BUG(show selected data) - ReAssign data(but id doesnt impact result):
string v = CurrentEdit.ValTxt;
int? i= CurrentEdit.ValInt;
CurrentEdit.ValTxt = string.Empty;
CurrentEdit.ValInt = null;
StateHasChanged();
//await InvokeAsync(() => StateHasChanged());
CurrentEdit.ValTxt = v;
CurrentEdit.ValInt = i;

//CurrentEdit.ValTxt = CurrentEdit.ValTxt;
//StateHasChanged();
*/
}
catch (Exception ex)
{
Notification.ShowSQLErr(ex.Message);
}
}

//PARTIALLY WORKING, but not filtering:
Task ReadComboData(DropDownListReadEventArgs e)
{
try
{
var r = readDBDATA...
CurrentEdit.ComboSource = r;
Paging.CNT = p.Get<int>("CNT");
}
catch (Exception ex)
{
Notification.ShowSQLErr(ex.Message);
}
}
}

Incremental Search A grid that can be searched incrementally as one types in the search box.

On-demand Sort It should have the ability to do a toggle between ascending and descending sort order when the user taps on a column header.

Pagination It should provide customizable pagination so only one page worth of data is fetched at any given time.

Did I describe the jQuery Datatable functionality? It is because it is so good and having the equivalent of its server-side implementation equivalent in Blazor will be awesome.

Implementation Thoughts The control sends a predefined model to an event bound function as parameter. The model has the information like requested page, column-sort request, letters the user typed into the search box etc. The function fetches data based on the model and the grid updates dynamically.

 

The demos and examples for storing and retrieving GRID state uses the JavaScript localStorage.setItem and localStorage.getItem that work great.  As part of .NET 5 there's a Microsoft equivalent for accessing Local Storage using Microsoft.AspNetCore.Components.Server.ProtectedBrowserStorage.  I've found the behavior of these demos and examples will not work by simply replacing the JavaScript with .NET equivalents.  My experience is getting Circuit Handler exceptions that make these example not work.  

Although not a requirement since there's a JavaScript solution for local storage, I would like to recommend that since you partner closely with .NET team at Microsoft.  That your GRID development team test and provide examples with the Microsoft .NET 5 out-of-the-box local storage solution and resolve any incompatibilities for developers not wanting to use 1st party local storage solutions embedded within Microsoft Blazor.

 

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ADMIN EDIT

I made a sample test and things seemed to work for me, so I made a public example, you can find it in this pull request until it gets merged. I'm also attaching it to this post, but for anyone seeing this after a time - the public repository linked above is a better place to look for this in case more updates and information have been added since the time of writing this.

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