自从。net 5以来，我们现在有了AllocateUnitializedArray，它可能会为建议的解决方案增加额外的(小)性能改进:

public static T[] ConcatArrays<T>(IEnumerable<T[]> arrays)
{
    var result = GC.AllocateUnitializedArray<T>(arrays.Sum(a => a.Length));
    var offset = 0;
    foreach (var a in arrays)
    {
        a.CopyTo(result, offset);
        offset += a.Length;
    }
    return result;
}

创建和扩展方法来处理null

public static class IEnumerableExtenions
{
    public static IEnumerable<T> UnionIfNotNull<T>(this IEnumerable<T> list1, IEnumerable<T> list2)
    {
        if (list1 != null && list2 != null)
            return list1.Union(list2);
        else if (list1 != null)
            return list1;
        else if (list2 != null)
            return list2;
        else return null;
    }
}

试试这个:

ArrayLIst al = new ArrayList();
al.AddRange(array_1);
al.AddRange(array_2);
al.AddRange(array_3);
array_4 = al.ToArray();

这是我想到的。适用于可变数量的数组。

public static T[] ConcatArrays<T>(params T[][] args)
    {
        if (args == null)
            throw new ArgumentNullException();

        var offset = 0;
        var newLength = args.Sum(arr => arr.Length); 
        var newArray = new T[newLength];

        foreach (var arr in args)
        {
            Buffer.BlockCopy(arr, 0, newArray, offset, arr.Length);
            offset += arr.Length;
        }

        return newArray;
    }

.．.

var header = new byte[] { 0, 1, 2};
var data = new byte[] { 3, 4, 5, 6 };
var checksum = new byte[] {7, 0};
var newArray = ConcatArrays(header, data, checksum);
//output byte[9] { 0, 1, 2, 3, 4, 5, 6, 7, 0 }

连接多个数组的简单代码:

string[] arr1 = ...
string[] arr2 = ...
string[] arr3 = ...    
List<string> arr = new List<string>(arr1.Length + arr2.Length + arr3.Length);
arr.AddRange(arr1);
arr.AddRange(arr2);
arr.AddRange(arr3);
string[] result = arr.ToArray();

如果你不想删除重复的，那么试试这个

使用LINQ:

var arr1 = new[] { 1, 2, 3, 4, 5 };
var arr2 = new[] { 6, 7, 8, 9, 0 };
var arr = arr1.Concat(arr2).ToArray();