.NET Addict
A glimpse into the daily affairs of an ASP.NET MVC developer by Nathan Taylor.
Monday, May 7, 2012
C# Truncate String - Whole Words
This is an update to my original string truncate helper which can be set to respect whitespace when terminating a string. This version will start at the character index specified as max length and then iterate back to the first instance of whitespace (if it exists), thus keeping whole words intact.public static string Truncate(this string str, int maxLength, bool onlyOnWhiteSpace = false, bool appendEllipses = false) {
if (str == null || maxLength >= str.Length)
{
return str;
}

if (onlyOnWhiteSpace
&& !char.IsWhiteSpace(str[maxLength])
&& str.Substring(0, maxLength).Any(char.IsWhiteSpace))
{
for (; maxLength >= 0; maxLength--)
{
if (char.IsWhiteSpace(str[maxLength]))
{
break;
}
}
}

return str.Substring(0, maxLength) + (appendEllipses ? "..." : "");
}
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Nathan Taylor
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1:59 PM
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c#,
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Tuesday, November 22, 2011
ASP.NET MVC Comma Separated Values Model Binder
In some scenarios such as data filtering it becomes necessary to pass multiple values to a single collection-typed request parameter. In typical flows this is achieved by passing multiple pairs of key and value parameters to the request.
/path/to/foo?key=value1&key=value2&key=value3 
While this works well, sometimes it is desirable to have something that is more human-readable. In an effort to satisfy that requirement, I have built a custom model binder to handle passing multiple values to a single parameter in the form of a single comma separated value.
/path/to/foo?key=value1,value2,value3 
This CommaSeparatedValuesModelBinder supports both generic collections and standard array types so long as the underlying type of the collection inherits from IConvertible (int, string, etc). In addition to supporting a comma separated value assignment, the implementation also maintains support for the default format of multiple key and value pairs. 
Here's the code:
public class CommaSeparatedValuesModelBinder : DefaultModelBinder
{
private static readonly MethodInfo ToArrayMethod = typeof(Enumerable).GetMethod("ToArray");

protected override object GetPropertyValue(ControllerContext controllerContext, ModelBindingContext bindingContext, 
PropertyDescriptor propertyDescriptor, IModelBinder propertyBinder)
{
if (propertyDescriptor.PropertyType.GetInterface(typeof (IEnumerable).Name) != null)
{
var actualValue = bindingContext.ValueProvider.GetValue(propertyDescriptor.Name);

if (actualValue != null && !String.IsNullOrWhiteSpace(actualValue.AttemptedValue) &&
actualValue.AttemptedValue.Contains(","))
{
var valueType = propertyDescriptor.PropertyType.GetElementType() ??
propertyDescriptor.PropertyType.GetGenericArguments().FirstOrDefault();

if (valueType != null && valueType.GetInterface(typeof (IConvertible).N