by Mads Kristensen
30. January 2007 17:54
In many different scenarios we need to check if a string can be converted into an
integer e.g. This could be when we work with query strings and need to check
if they match a certain data type. In VB.NET you can use the IsNumeric and IsDate
functions, but that's about it. You are left to your own data type checking logic
the rest of the time. It would be cool if we could have a method that could check
all data types that is represented by strings such as integers, guids, booleans etc.
Here is a method that does just that. It can check all the string based types and
also enums.
/// <summary> /// Checks
the specified value to see if it can be /// converted
into the specified type. /// <remarks> /// The
method supports all the primitive types of the CLR /// such
as int, boolean, double, guid etc. as well as other /// simple
types like Color and Unit and custom enum types. /// </remarks> /// </summary> /// <param
name="value">The value to check.</param> /// <param
name="type">The type that the value will be
checked against.</param> /// <returns>True
if the value can convert to the given type, otherwise false.</returns> public static bool CanConvert(string value,
Type type) { if (string.IsNullOrEmpty(value) || type == null) return false;
System.ComponentModel.TypeConverter conv = System.ComponentModel.TypeDescriptor.GetConverter(type); if (conv.CanConvertFrom(typeof(string)))
{ try { conv.ConvertFrom(value); return true;
} catch {
} } return false;
}
Example of use
Let's try some different examples
CanConvert("12", typeof(int)); // returns
true CanConvert("f637a876-9d58-4229-9559-a5e42a95fdac ", typeof(Guid)); // returns
true CanConvert("Backspace", typeof(System.ConsoleKey)); // returns
true CanConvert("10px", typeof(System.Web.UI.WebControls.Unit)); // returns
true CanConvert("red", typeof(System.Drawing.Color)); // returns
true
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Tags:
Server-side
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