Work with Data Grid rows

[GevorDanielyan]

Hello everyone.

I have a component which is editable Data Grid. When I edit row, I need to take the current values before edit for some calculation purposes. How can I do that?

My component is

@using Grpc.Core
@using Blazorise.DataGrid
@using GrpcService.BlazorApp.Models
@using Google.Protobuf.WellKnownTypes
@using ValuesgRPCService
@inject ILogger<GoldBar> _logger
@inject ValuesgRPCService.ValuesService.ValuesServiceClient valuesServiceClient

<DataGrid TItem="ValuesModel"
          Data="_values"
          Virtualize
          Editable
          EditMode="DataGridEditMode.Popup"
          RowUpdated="@OnRowUpdated"
          Hoverable="true"
          HeaderThemeContrast="ThemeContrast.Light"
          Bordered="true"
          Style="font-size: .80em;"
          Responsive>
    <DataGridColumns>
        <DataGridCommandColumn Context="dataGridContext"
                               NewCommandAllowed="false"
                               EditCommandAllowed="true"
                               DeleteCommandAllowed="false"
                               TItem="ValuesModel">
            <EditCommandTemplate>
                <Button Color="Color.Primary" Clicked="dataGridContext.Clicked">Edit</Button>
            </EditCommandTemplate>
        </DataGridCommandColumn>
        <DataGridColumn TItem="ValuesModel" Field="@nameof(ValuesModel.Description)" Caption="Description" Sortable="false" />
        <DataGridColumn TItem="ValuesModel" Field="@nameof(ValuesModel.Value)" Caption="Value" Editable="true" Sortable="false" />
    </DataGridColumns>
</DataGrid>

@code {
    [Inject] IMessageService? MessageService { get; set; }

    private List<ValuesModel>? _values = new List<ValuesModel>();

    protected override async Task OnInitializedAsync()
    {
        await GetGoldBarValuesAsync();
        await base.OnInitializedAsync();
    }

    private async Task GetGoldBarValuesAsync()
    {
        var request = new Empty();
        try
        {
            using (var call = valuesServiceClient.GetValues(request))
            {
                await foreach (var response in call.ResponseStream.ReadAllAsync())
                {
                    var goldValueResponse = new ValuesModel
                        {
                            Description = response.Description,
                            Value = response.Value
                        };
                    _values!.Add(goldValueResponse);
                }
            }
        }
        catch (RpcException ex) when (ex.StatusCode == StatusCode.Internal)
        {
            _logger.LogError(ex.Message);
            throw;
        }
    }

    private async Task OnRowUpdated(SavedRowItem<ValuesModel, Dictionary<string, object>> e)
    {
        var goldValue = e.Item;
        UpdateValuesRequest request = new UpdateValuesRequest
            {
                Value = goldValue.Value,
                Description = goldValue.Description
            };

        var response = await valuesServiceClient.UpdateValueAsync(request);
        _logger.LogInformation("Update {0} value", request.Description);

        if (response.Message is null)
        {
            await MessageService!.Error("Cannot update value");
        }

        await MessageService!.Info("Updated successfully");

    }

}

In OnRowUpdated method I get already input value in SavedRowItem<ValuesModel, Dictionary<string, object>> e
But I need to get current values as well for some calculations.

Thanks in advance.

[David-Moreira]

If I remember correctly that argument, SavedRowItem<ValuesModel, Dictionary<string, object>> e does precisely that.
ValuesModel has the old values.
Dictionary<string, object> has the new values to be commited on the ValuesModel.

[GevorDanielyan]

In SavedRowItem<ValuesModel, Dictionary<string, object>> e I'm getting already new values if changing something.

[David-Moreira]

Hello, then there's the other callback RowUpdating that I'm pretty sure it works like that. Can you try that one?

But I'll be remembering how RowUpdated works as it would be redundant to have both the new values in the model and in the values dictionary?

[GevorDanielyan]

Hello @David-Moreira , thank you for your reply. I used RowUpdating, and have wrote this method for getting current row value.

private async Task OnRowUpdating(CancellableRowChange<ValuesModel, Dictionary<string, object>> rowValues)
    {
        var item = rowValues.Item;

        var values = rowValues.Values;

        if (item.Description == "BUY" || item.Description == "SALE" || item.Description == "AVG")
        {
            bool dictionaryValues = values.TryGetValue("Value", out object? value);
            decimal difference = Math.Abs(Convert.ToDecimal(item.Value!) - Convert.ToDecimal(value!)) / Convert.ToDecimal(item.Value!) * 100;

            if (difference > 5)
            {
                await MessageService!.Error("Difference more than 5%");
            }

        }
    }

But there is another issue, related IMessageService. In this part, suppose that difference is greater than 5, but
await MessageService!.Error("Difference more than 5%"); is not working, that is, I don't see error message.

if (difference > 5)
            {
                await MessageService!.Error("Difference more than 5%");
            }

[GevorDanielyan]

The last issue solved already. The problem was in RowUpdating and RowUpdated events, that is, I use they at the same time in my grid. Here in this issue, I solve like this.

@using Grpc.Core
@using Blazorise.DataGrid
@using GrpcService.BlazorApp.Models
@using Google.Protobuf.WellKnownTypes
@using ValuesgRPCService
@inject ILogger<GoldBar> _logger
@inject ValuesgRPCService.ValuesService.ValuesServiceClient valuesServiceClient

<DataGrid TItem="ValuesModel"
          Data="_values"
          Virtualize
          Editable
          EditMode="DataGridEditMode.Popup"
          RowUpdating="@OnRowUpdating"
          @bind-SelectedRow="valuesModel"
          Hoverable="true"
          HeaderThemeContrast="ThemeContrast.Light"
          Bordered="true"
          Style="font-size: .80em;"
          Responsive>
    <DataGridColumns>
        <DataGridCommandColumn Context="dataGridContext"
                               NewCommandAllowed="false"
                               EditCommandAllowed="true"
                               DeleteCommandAllowed="false"
                               TItem="ValuesModel">
            <EditCommandTemplate>
                <Button Color="Color.Primary" Clicked="dataGridContext.Clicked">Edit</Button>
            </EditCommandTemplate>
        </DataGridCommandColumn>
        <DataGridColumn TItem="ValuesModel" Field="@nameof(ValuesModel.Description)" Caption="Description" Sortable="false" />
        <DataGridColumn TItem="ValuesModel" Field="@nameof(ValuesModel.Value)" Caption="Value" Editable="true" Sortable="false" />
    </DataGridColumns>
</DataGrid>

@code {

    [Inject] IMessageService? MessageService { get; set; }
    DataGrid<ValuesModel> dataGrid = new DataGrid<ValuesModel>();
    private List<ValuesModel>? _values = new List<ValuesModel>();
    ValuesModel valuesModel = new ValuesModel();

    protected override async Task OnInitializedAsync()
    {
        await GetGoldBarValuesAsync();
        await base.OnInitializedAsync();
    }

    private async Task GetGoldBarValuesAsync()
    {
        var request = new Empty();
        try
        {
            using (var call = valuesServiceClient.GetValues(request))
            {
                await foreach (var response in call.ResponseStream.ReadAllAsync())
                {
                    var goldValueResponse = new ValuesModel
                        {
                            Description = response.Description,
                            Value = response.Value
                        };
                    _values!.Add(goldValueResponse);
                }
            }
        }
        catch (RpcException ex) when (ex.StatusCode == StatusCode.Internal)
        {
            _logger.LogError(ex.Message);
            throw;
        }
    }

    private async Task OnRowUpdating(CancellableRowChange<ValuesModel, Dictionary<string, object>> rowValues)
    {
        var values = rowValues.Values;
        bool dictionaryValues = values.TryGetValue("Value", out object? value);
        if (rowValues.Item.Description == "BUY" || rowValues.Item.Description == "SALE" || rowValues.Item.Description == "AVG")
        {
            // Calculate difference betwen current and new values and get absolute value
            decimal difference = Math.Abs(Convert.ToDecimal(rowValues.Item.Value!) - Convert.ToDecimal(value!)) / Convert.ToDecimal(rowValues.Item.Value!) * 100;

            if (difference > 5)
            {
                await MessageService!.Error("Difference more than 5%");
                return;
            }
        }

        UpdateValuesRequest request = new UpdateValuesRequest
            {
                Value = Convert.ToDouble(value),
                Description = rowValues.Item.Description
            };

        var response = await valuesServiceClient.UpdateValueAsync(request);
        _logger.LogInformation("Update {0} value", request.Description);

        if (response.Message is null)
        {
            await MessageService!.Error("Cannot update value");
        }

        await MessageService!.Info("Updated successfully");

    }
}