无法将int []类型隐式转换为int？[]

在我的示例类中,它包含IdValues int?[].值来自具有Id作为关键字段的其他类.

//Database class
public class SampleValues // this is a entity that i want to collect the deatil id
{
    public int Id { get; set; }
    public int?[] SampleDetailIdValue { get; set; }
}

public class SampleDetailValues // this is the detail entity
{
    public int Id { get; set; }
}


// The error code
if (sampleDetails.Count > 0)
{
    sample.IdValues = sampleDetails.Select(s => s.Id).ToArray(); // << The error occurred this line.
}

错误是无法将类型隐式转换int[]为int?[]