获取指定目录下多种格式的文件

System.IO.Dirctory.GetFiles(string path, string searchPattern)方法不支持选择多种格式的文件。

下面提供一个通过OpenFileDialog中支持的文件过滤器Filter获取多种格式文件的方法。

/// <summary>
/// 根据文件过滤器获取指定目录下的文件
/// </summary>
/// <param name="directoryPath"></param>
/// <param name="filter">Example:"doc file|*.doc|txt file|*.txt"</param>
/// <returns></returns>
public List<string> GetDirectoryFiles(string directoryPath, string filter)
{
    if (Directory.Exists(directoryPath) == false)
    {
        throw new DirectoryNotFoundException(String.Format("/'{0}/' is not found!"));
    }
    List<string> extensions = this.GetFilterExtensions(filter);
    
    List<string> files = new List<string>();
    if (extensions.Count > 0)
    {
        for (int i = 0; i < extensions.Count; i++)
        {
            files.AddRange(this.ArrToList(Directory.GetFiles(directoryPath, extensions[i])));
        }
    }
    else
    {
        files.AddRange(this.ArrToList(Directory.GetFiles(directoryPath)));
    }
    return files;
}

/// <summary>
/// 解析文件过滤器
/// </summary>
/// <param name="filter">Example:"doc file|*.doc|txt file|*.txt"</param>
/// <returns></returns>
private List<string> GetFilterExtensions(string filter)
{
    List<string> extensions = new List<string>();
    if (String.IsNullOrEmpty(filter) == false)
    {
        string[] strArr = filter.Split(new char[] { '|' });
        for (int i = 1; i < strArr.Length; i += 2)
        {
            string temp = strArr[i];
            if (temp.StartsWith("*.") == false)
                temp = "*." + temp;
            if (extensions.Contains(temp) == false)
                extensions.Add(temp);
        }
    }
    return extensions;
}

/// <summary>
/// 将数组转换为List
/// </summary>
/// <param name="strArr"></param>
/// <returns></returns>
private List<string> ArrToList(string[] strArr)
{
    List<string> strList = new List<string>();
    if (strArr != null && strArr.Length > 0)
    {
        for (int i = 0; i < strArr.Length; i++)
            strList.Add(strArr[i]);
    }
    return strList;
}