0

我有一个类的公共属性,我的输出详细信息行是这样写的:

public static long OutputListToFile(StreamWriter writer, List<DocMetaData> listData)
    {
        StringBuilder md = new StringBuilder();
        int rowcount = 0;
        foreach (var c in listData)
        {
            md.Append(c.Section); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.DocClass); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.Meeting); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.Agency); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.Country); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.Comment); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.Title); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.Folder); md.Append(DocMetaData.SEPARATOR);
            md.Append(c.File); md.Append(DocMetaData.CARRIAGE_RETURN);
            try
            {
                writer.WriteLine(md.ToString());
                rowcount++;
            }
            catch (Exception ex)
            {
                log.Fatal("Error in OutputListToFile:\r\n", ex);
            }
        }
        return rowcount;
    }

md.Append 语句当前必须按上述确切顺序放置,以便与编写第一行的例程匹配:

private void OutputColumnNamesAsFirstLine(StreamWriter writer)
    {
        StringBuilder md = new StringBuilder();
        PropertyInfo[] columns;
        columns = typeof(DocMetaData).GetProperties(BindingFlags.Public |
                                                      BindingFlags.Instance);
        int i = 0;
        foreach (var columnName in columns)
        {
            i++;
            md.Append(columnName.Name); md.Append(DocMetaData.SEPARATOR);
        }
        writer.WriteLine(md.ToString());
    }

有没有办法可以重写 OutputListToFile 中的 foreach 循环,这样我就可以消除这种排序依赖性。这是 DocMetaData 类的片段:

 public class DocMetaData
{
    public const string SEPARATOR = "\t";       // horizontal tab is delimiter
    public const string CARRIAGE_RETURN = "\r";

    public string Section { get; set; }
    public string DocClass { get; set; }
    public string Meeting { get; set; }
    public string Agency { get; set; }
    public string Country { get; set; }
    public string Comment { get; set; }
    public string Title { get; set; }
    public string Folder { get; set; }
    public string File { get; set; }
4

3 回答 3

2

如果您考虑使用属性注释属性,则此解决方案将起作用:

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false, Inherited = true)]
public class OrdinalPositionAttribute : Attribute
{
    public int Position { get; private set; }

    public OrdinalPositionAttribute(int position)
    {
        Position = position;
    }
}

public class DocMetaData
{
    public const string SEPARATOR = "\t";       // horizontal tab is delimiter
    public const string CARRIAGE_RETURN = "\r";

    [OrdinalPosition(0)]
    public string Section { get; set; }
    [OrdinalPosition(1)]
    public string DocClass { get; set; }
    [OrdinalPosition(2)]
    public string Meeting { get; set; }
    [OrdinalPosition(3)]
    public string Agency { get; set; }
    [OrdinalPosition(4)]
    public string Country { get; set; }
    [OrdinalPosition(5)]
    public string Comment { get; set; }
    [OrdinalPosition(6)]
    public string Title { get; set; }
    [OrdinalPosition(7)]
    public string Folder { get; set; }
    [OrdinalPosition(8)]
    public string File { get; set; }

    private void OutputColumnNamesAsFirstLine(StreamWriter writer)
    {
        StringBuilder md = new StringBuilder();
        var columns = Utility.GetOrderedMembers(typeof(DocMetaData));

        int i = 0;
        foreach (var columnName in columns)
        {
            i++;
            md.Append(columnName.Name); md.Append(DocMetaData.SEPARATOR);
        }
        writer.WriteLine(md.ToString());
    }
}

public static class Utility
{
    public static IEnumerable<MemberInfo> GetOrderedMembers(Type type)
    {
        if (type == null)
            throw new ArgumentNullException("type");

        return CreateGetOrderedMembersEnumerable(type);
    }

    private static IEnumerable<MemberInfo> CreateGetOrderedMembersEnumerable(Type type)
    {
        return from member in type.GetMembers(BindingFlags.Public | BindingFlags.Instance)

               let ordinal = member.GetCustomAttributes(typeof(OrdinalPositionAttribute), true)
                                   .OfType<OrdinalPositionAttribute>().FirstOrDefault()

               where ordinal != null

               orderby ordinal.Position ascending

               select member;
    }
}

如果要获取属性的值,则需要调用返回的.Cast<PropertyInfo>()by 。IEnumerable<MemberInfo>GetOrderedMembers()

于 2011-08-08T23:03:21.347 回答
1

考虑Dictionary<string, string>为您的 DocMetaData(而不是类)使用 a,其中第一个是字段名称,第二个是值。然后,您可以使用您的列数组检索值。

于 2011-08-08T22:48:47.433 回答
1

我不确定这是你想要的,但如果你想以相同的顺序编写所有属性的内容column,你可以使用它:

foreach (var c in listData)
{
    foreach (var column in columns)
    {
        md.Append(column.GetValue(c, null));
    }
}

此代码不使用分隔符和终止符作为您的原始代码,但我相信您可以轻松解决这个问题。

于 2011-08-08T23:47:26.927 回答