How to prevent OnSelectedItemChanged Call after Refresh

Hi,

Each time the page is reloaded or clicked, the OnSelectedItemChanged for Select is executed. How can I prevent this? The same behavior can be seen on the Ant Blazor Page. The OnSelectedItemChanged should only be called, if I select an Item

<Select @bind-Value="@context.ColorState" 
   	DefaultValue = "@context.ColorState"
   	TItemValue="ColorState" 
   	TItem="ColorState"
   	OnSelectedItemChanged="(value)=>UpdateColor(context)">
   <SelectOptions>
   	@foreach (ColorState color in Enum.GetValues(typeof(ColorState)))
   	{
   		<SelectOption TItemValue="ColorState" TItem="ColorState" Value="@color" />
   	}   
   </SelectOptions>
</Select>  

[anranruye]

@anddrzejb

I agree with @minas15 , and this is not the only issue with OnSelectedItemChanged. When set the Value programmatically, OnSelectedItemChanged is not triggered.

And I basicly agree with @susahin80 .

there might be a scenario when value is changed by some external service

Microsoft suggests that paramter properties should only be set by binding values. However, it’s true that we don’t always follow this rule. I think we should act base on the source of Value when it changes. If the Value is from the binding Value then we should not trigger ValueChanged, otherwise there will be an unnecessary rerendering.

[anddrzejb]

@anranruye thank you for sharing the issue. It was a worthwhile read. And I agree with your understanding of properties use when marked with [Parameter] attribute. Although I am not sure if the suggestion of forcing only {get;set;} is entirely warranted. Of course, without understanding of possible underlying problems, it is a good solution, but in the hands of a programmer well versed in blazor internals, using setters (or getters) can help keeping the code cleaner & leaner.

But now I can see that there was a misunderstanding (or at least I think there was). I was not referring to changing value of the child component (so the [Parameter] Value {get;set;}, I was rather referring to changing the parent’s variable that is bound to Value parameter. But the more thought I gave to the issue, the more I think @susahin80 is actually correct.