Queue删除其中一个元素比较麻烦，这是一个重码校验的类，主要处理是用Dictionary代替Queue了。目前使用下来还算稳定。代码贴出来给有缘人参考。
/// <summary>
/// 用Dictionary实现的重码校验队列
/// 1、支持先进先出
/// 2、支持移除队列里元素
/// 3、支持从文件和数据库（外部数据源）里加载队列
/// 4、支持把当前队列数据序列化成二进制文件
/// </summary>
public class RepeatCodeChecker : ConcurrentDictionary<long, string>
{
/// <summary>
/// 工作计数
/// </summary>
public int WorkCount { get; set; }
/// <summary>
/// 最大元素个数
/// </summary>
public int MaxCount { get; set; }
/// <summary>
/// 加载已有数据到队列
/// </summary>
public Action<List<string>> LoadItemFromDataSource;
/// <summary>
/// 检查条码是否重复,并确定是否加入队列
/// </summary>
public Func<string, bool, bool> CheckIsRepeat;
/// <summary>
/// 将队列已有数据序列化成二进制文件
/// </summary>
public Action<string> SaveToBinaryFile;
/// <summary>
/// 从二进制文件里加载队列
/// </summary>
public Func<string, bool> LoadQueueFormFile;
/// <summary>
/// 添加一个元素到队列末尾
/// </summary>
/// <param name="code"></param>
public void Enqueue(string code)
{
var key = DateTime.Now.Ticks;
if (ContainsKey(key))
{
key += (Count + );
}
TryAdd(key, code);
WorkCount++;
//如果达到最大元素个数移除最前面的元素
if (MaxCount != && Count > MaxCount)
{
Dequeue();
}
}
/// <summary>
/// 从队列移除第一个元素
/// </summary>
/// <returns></returns>
public string Dequeue()
{
var minKey = this.Min(k => k.Key);
string val;
TryRemove(minKey, out val);
return val;
}
/// <summary>
/// 从队列里删除一个已经存在的元素
/// </summary>
/// <param name="code"></param>
/// <returns></returns>
public bool RemoveCode(string code)
{
try
{
var valObj = this.FirstOrDefault(t => t.Value == code);
string val;
TryRemove(valObj.Key, out val);
return true;
}
catch
{
return false;
}
} public RepeatCodeChecker()
{
//从外部数据源加载队列
LoadItemFromDataSource = (list) =>
{
foreach (string code in list)
Enqueue(code);
};
//校验重码的委托声明
CheckIsRepeat = (val, isAddtoQueue) =>
{
bool result = this.Any(item => item.Value == val);
//不存在且需要加入则自动加入队列
if (!result && isAddtoQueue)
{
Enqueue(val);
}
return result;
};
//序列化成二进制文件
SaveToBinaryFile = (filePath) =>
{
if (File.Exists(filePath))
File.Delete(filePath);
using (FileStream fsWrite = new FileStream(filePath, FileMode.Create, FileAccess.Write))
{
BinaryFormatter bf = new BinaryFormatter();
try
{
bf.Serialize(fsWrite, this);
}
catch (Exception e)
{
throw new Exception(e.Message);
}
finally
{
fsWrite.Flush();
fsWrite.Close();
}
}
};
//从文件加载队列
LoadQueueFormFile = (filePath) =>
{
if (File.Exists(filePath))
{
using (FileStream fs = new FileStream(filePath, FileMode.Open))
{
BinaryFormatter bf1 = new BinaryFormatter();
try
{
Dictionary<string, string> dict = bf1.Deserialize(fs) as Dictionary<string, string>;
if (dict != null)
{
foreach (var item in dict)
{
Enqueue(item.Value);
}
}
return true;
}
catch
{
return false;
}
finally
{
fs.Close();
}
}
}
return false;
};
}
/// <summary>
/// 获取最前面的元素
/// </summary>
/// <returns></returns>
public string FirstOrDefault()
{
if (Count == )
return string.Empty;
long minKey = this.Min(k => k.Key);
return this[minKey];
}
/// <summary>
/// 获取最前面的元素
/// </summary>
/// <returns></returns>
public string LastOrDefault()
{
if (Count == )
return string.Empty;
long maxKey = this.Max(k => k.Key);
return this[maxKey];
}
}