Question
So i have been stuck trying to get a simple onchange to fire when a select dropdown value changes. Like so:
<select class="form-control d-flex" onchange="(dostuff())">
@foreach (var template in templatestate.templates)
{
<option value=@template.Name>@template.Name</option>
}
</select>
with the method being called:
void dostuff()
{
Console.WriteLine("first spot is firing");
_template = templatestate.templates.FirstOrDefault(x => x.Name ==
_template.Name);
Console.WriteLine("second spot is firing");
}
The result I get it no matter how i try to reorient it is this error in the browser.
Uncaught Error: System.ArgumentException: There is no event handler with ID 0
Is there something obvious and key that I am missing? Because I have a button onclick event that works just fine in the same page.
Accepted Answer
Your answer should be in the cshtml:
<select onchange=@DoStuff>
@foreach (var template in templates)
{
<option value=@template>@template</option>
}
</select>
Then your @functions should look like:
@functions {
List<string> templates = new List<string>() { "Maui", "Hawaii", "Niihau", "Kauai", "Kahoolawe" };
string selectedString = "Maui";
void DoStuff(ChangeEventArgs e)
{
selectedString = e.Value.ToString();
Console.WriteLine("It is definitely: " + selectedString);
}
}
You could also just use a bind...
<select bind="@selectedString">
but onchange=@DoStuff allows you to perform logic on selection.
Popular Answer
Above answer didn't work for me, got compilation error.
below is my working code.
@inject HttpClient httpClient
@if (States != null)
{
<select id="SearchStateId" name="stateId" @onchange="DoStuff" class="form-control1">
<option>@InitialText</option>
@foreach (var state in States)
{
<option value="@state.Name">@state.Name</option>
}
</select>
}
@code {
[Parameter] public string InitialText { get; set; } = "Select State";
private KeyValue[] States;
private string selectedString { get; set; }
protected override async Task OnInitializedAsync()
{
States = await httpClient.GetJsonAsync<KeyValue[]>("/sample-data/State.json");
}
private void DoStuff(ChangeEventArgs e)
{
selectedString = e.Value.ToString();
Console.WriteLine("It is definitely: " + selectedString);
}
public class KeyValue
{
public int Id { get; set; }
public string Name { get; set; }
}
}
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