Blazor stored variable reverting after function completion

Question

I have a fairly simple blazor server side app and am writing data to my db based on drag/drop. I have my functions working to get the id/type at dragstart and the same at drop however the data I store from the dragstart function reverts/dissappears when I start my drop function. What am I doing wrong?

dragged Element

<table class="table AssignmentsTable" draggable="true"
@ondragstart="@(e => AssignmentOnDragStart(item.Id, "Location"))"
@ondragstart:stopPropagation>
    <tr>
        <td>
            <span>@item?.Description</span>
        </td>
    </tr>
</table>

dropped Element

<h5 @ondrop="@(e => AssignmentOnDrop((ParentID ?? 0), "Company"))" ondragover="event.preventDefault()">@company.Name</h5>

.razor (code)

string storedAssigneeType;
int storedAssigneeID;
string storedAssignmentType;
int storedAssignmentID;


public async void AssignmentOnDragStart(int id, string type)
{
    await JSRuntime.InvokeVoidAsync("console.log", $"Before: {type}: {id.ToString()}");
    storedAssigneeID = id;
    storedAssigneeType = type;
    await JSRuntime.InvokeVoidAsync("console.log", $"After: {storedAssigneeType}: {storedAssigneeID.ToString()}");
}

public async void AssignmentOnDrop(int id, string type)
{
    await JSRuntime.InvokeVoidAsync("console.log", $"Stored Assignee: {storedAssigneeType}: {storedAssigneeID.ToString()}");
    await JSRuntime.InvokeVoidAsync("console.log", $"{type}: {id.ToString()}");
    storedAssignmentID = id;
    storedAssignmentType = type;
    var result = @Service.AddAssignment(storedAssigneeType, storedAssigneeID, storedAssignmentType, storedAssignmentID);
    await JSRuntime.InvokeVoidAsync("console.log", $"{result.ToString()}");

}

I'm new so I've tried a lot of the wrong things. I tried {get;set;} for the variables, public/private, and some other items. I know I am just doing something dumb but am at a loss (or its too late at night). There were 2 other questions on the stack that seemed very similar but neither produced a working solution. Help please and thanks.

Mayur Ekbote · Accepted Answer · 2023-10-25 19:27:33Z

0

Don't use async void, use async Task. Your code should look like this:

public async Task AssignmentOnDragStart(int id, string type)

public async Task AssignmentOnDrop(int id, string type)

@ondragstart="@(async(e) => await AssignmentOnDragStart(item.Id, "Location"))"

@ondrop="@(async(e) => await AssignmentOnDrop((ParentID ?? 0), "Company"))"

Also, don't use console logging for this. You can do a simple Console.WriteLine and check the output on the process console. That will enable you to write synchronous methods.

answered Oct 25, 2023 at 19:27

Mayur Ekbote

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1 Comment

aedom1 Over a year ago

Thanks for the help Mayur. What you posted didn't solve my problem but thank all the same. I have posted a link to the question that ended up getting me where I needed. Sleep and a Monster or two always seem to help.

aedom1 · Accepted Answer · 2023-10-26 02:54:42Z

0

After screwing around for quite awhile I ended up getting it to work with question 53913396. I had tried some similar items from the MS documentation but got a few minor things wrong. Thanks all.

edited Oct 26, 2023 at 2:54

answered Oct 26, 2023 at 2:52

aedom1

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1 Comment

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