C# 将实体属性传递给一个 function 在 LINQ 中使用

Question

Imagine I have a class like this:

public class BaseRepo<T> where T : class
{
    private readonly DbSet<T> table;

    public BaseRepo(MyDbContext context)
    {
        this.table = context.Set<T>();
    }
}

I want to implement the following logic in to this class.

string GenerateUniqueStringFor(PropertyName)
{
    string val = string.Empty;    

    do
    {
        val = GenerateRandomString();
    }
    while (this.table.FirstOrDefault(x => x.PropertyName == val) is not null);

    return val;
}

The problem is I don't know how to pass Property/PropertyName. The ideal way for calling it would be:

string val = _myRepo.GenerateUniqueStringFor(x => x.PropertyName);

Answer 1

If I understand correctly, you can try to pass a delegate Func

string GenerateUniqueStringFor(Func<T,string> func)
{
    string val = string.Empty;    

    do
    {
        val = GenerateRandomString();
    }
    while (this.table.FirstOrDefault(x => func(x) == val) is not null);

    return val;
}