Passing property delegate into Blazor component giving 'does not take 1 argument' error - delegates

Question

I am trying to pass a property as a delegate into a Blazor component. However, I get a Delegate 'Func<Pen, int, stirng>' does not take 1 argument error. And uncertain what the correct syntax should be.
This is the component:
#typeparam TItem
<div class="MarelAutoComplete">
<div class="MarelAutoCompleteList">
#foreach (var item in Data.Select(Property))
{
...
}
</div>
</div>
#code {
[Parameter]
public List<TItem> Data { get; set; }
[Parameter]
public Func<TItem, string> Property { get; set; }
}
Below is the calling Code:
<MyComponent TItem="Pen"
TValue="myVal"
Data="Pens"
Property="pen => pen.PenNumber" /> // Error On This Line.
#code {
List<Pen> Pens { get; set; }
}

Answer 1

The error you report is Delegate 'Func<Pen, int, string>' does not take 1 argument yet Property is defined as Func<TItem, string>.
Func<TItem, string> Property says I want a function that looks like this:
string MyMethod(TItem item)
Your anonymous function is pen => pen.PenNumber, with Property expecting pen.PenNumber as a string. Is it?
Here's a simplified working version of what you're doing:
TextBox.razor
#typeparam TItem
<h3>#Value</h3>
#foreach (var item in Data.Select(this.Property))
{
<div>#item</div>
}
#code {
[Parameter] public string Value { get; set; } = "Bonjour";
[Parameter] public Func<TItem, string> Property { get; set; }
[Parameter] public List<TItem> Data { get; set; }
}
Index.razor
#page "/"
#using Blazor.Starter.Data
<div>
<TextBox TItem="Model" Data="models" Property="item => item.Value"></TextBox>
</div>
#code {
public string GetProperty(Model model)
{
return model.Value;
}
public List<Model> models => new List<Model>()
{
new Model() { Value = "Fred"},
new Model() { Value = "Jon"},
new Model() { Value = "Bob"},
};
public class Model
{
public string Value { get; set; }
}
}

Answer 2

The issue was a simple syntax issue. When defining input functions this way, the input variables need to be enclosed in brackets.
It worked by changing this:
Property="pen => pen.PenNumber"
to this:
Property="(pen) => pen.PenNumber"