处理大小的简便方法:

public static class Extensions {
    public static int K(this int value) {
        return value * 1024;
    }
    public static int M(this int value) {
        return value * 1024 * 1024;
    }
}

public class Program {
    public void Main() {
        WSHttpContextBinding serviceMultipleTokenBinding = new WSHttpContextBinding() {
            MaxBufferPoolSize = 2.M(), // instead of 2097152
            MaxReceivedMessageSize = 64.K(), // instead of 65536
        };
    }
}

我创建了一个扩展方法来在下拉菜单中选择一个项目。

下面是代码

 public static class Utilities
{
    public enum DropDownListSelectionType
    {
        ByValue,
        ByText
    }

    public static void SelectItem(this  System.Web.UI.WebControls.DropDownList drp, string selectedValue, DropDownListSelectionType type)
    {
        drp.ClearSelection();
        System.Web.UI.WebControls.ListItem li;
        if (type == DropDownListSelectionType.ByValue)
            li = drp.Items.FindByValue(selectedValue.Trim());
        else
            li = drp.Items.FindByText(selectedValue.Trim());
        if (li != null)
            li.Selected = true;
    }}

此方法可以由以下代码行调用，以按文本进行选择

DropDownList1.SelectItem("ABCD", Utilities.DropDownListSelectionType.ByText);

或者按值选择

DropDownList1.SelectItem("11", Utilities.DropDownListSelectionType.ByValue);

上面的代码不选择任何东西，如果它不能找到传递进来的文本/值。

我很失望，. net框架更倾向于将文件和目录表示为字符串而不是对象，而且FileInfo和DirectoryInfo类型并不像我希望的那样强大。因此，我开始根据需要编写流畅的扩展方法，例如:

public static FileInfo SetExtension(this FileInfo fileInfo, string extension)
{
    return new FileInfo(Path.ChangeExtension(fileInfo.FullName, extension));
}

public static FileInfo SetDirectory(this FileInfo fileInfo, string directory)
{
    return new FileInfo(Path.Combine(directory, fileInfo.Name));
}

是的，你可以把这个放进codeplex

WhereIf()方法

var query = dc.Reviewer 
    .Where(r => r.FacilityID == facilityID) 
    .WhereIf(CheckBoxActive.Checked, r => r.IsActive); 

public static IEnumerable<TSource> WhereIf<TSource>(
    this IEnumerable<TSource> source,
    bool condition, Func<TSource, bool> predicate) 
{ 
    if (condition) 
        return source.Where(predicate); 
    else 
        return source; 
}

public static IQueryable<TSource> WhereIf<TSource>(
    this IQueryable<TSource> source,
    bool condition, Expression<Func<TSource, bool>> predicate) 
{ 
    if (condition) 
        return source.Where(predicate); 
    else 
        return source; 
}

我还为Where()扩展方法中的索引谓词添加了重载。为了更有趣，可以添加包含额外“else”谓词的风味。

我不想添加任何已经说过的东西，所以这里有一些我没有提到的东西。(如果这太长了，对不起):

public static class MyExtensions
{
    public static bool IsInteger(this string input)
    {
        int temp;

        return int.TryParse(input, out temp);
    }

    public static bool IsDecimal(this string input)
    {
        decimal temp;

        return decimal.TryParse(input, out temp);
    }

    public static int ToInteger(this string input, int defaultValue)
    {
        int temp;

        return (int.TryParse(input, out temp)) ? temp : defaultValue;
    }

    public static decimal ToDecimal(this string input, decimal defaultValue)
    {
        decimal temp;

        return (decimal.TryParse(input, out temp)) ? temp : defaultValue;
    }

    public static DateTime ToFirstOfTheMonth(this DateTime input)
    {
        return input.Date.AddDays(-1 * input.Day + 1);
    }

    // Intentionally returns 0 if the target date is before the input date.
    public static int MonthsUntil(this DateTime input, DateTime targetDate)
    {
        input = input.ToFirstOfTheMonth();

        targetDate = targetDate.ToFirstOfTheMonth();

        int result = 0;

        while (input < targetDate)
        {
        input = input.AddMonths(1);
            result++;
        }

        return result;
    }

    // Used for backwards compatibility in a system built before my time.
    public static DataTable ToDataTable(this IEnumerable input)
    {
        // too much code to show here right now...
    }
}

轻松序列化对象为XML:

public static string ToXml<T>(this T obj) where T : class
{
    XmlSerializer s = new XmlSerializer(obj.GetType());
    using (StringWriter writer = new StringWriter())
    {
        s.Serialize(writer, obj);
        return writer.ToString();
    }
}

"<root><child>foo</child</root>".ToXml<MyCustomType>();