Validation techneques?

[venomation]

I have decided that I need a better way of validating data. I currently have various objects that can validate information, for example:

if(TextBoxValidator.IsValidTextBox(tbText))...

Also I tend to use the Debug.Assert() methods often, making sure that null or invalid states of variables are shown. Its starting to get repetitive when I validate:

if(fileDetails.ToString() == string.Empty || map == null) return Common.ReturnResult.Failed;
if(map.StaticImages == null || map.Tiles == null) return Common.ReturnResult.Failed;
if(map.Infomation.Columns == 0 || map.Infomation.RootContentFolder == string.Empty || map.Infomation.Rows == 0 || map.Infomation.TileSize == 0)
return Common.ReturnResult.Failed;

There must be a better way to validate methods input and such than this! :-D Any suggestions, Thanks :doh:

[Keith Barrow]

One way is to avoid nulls in the first place, but if you need to check , here is a start, it is longer but clearer to read:

...

bool Success(footype map) //This isn't the best name
{
if(map.StaticImages == null)
return false;
if(map.Tiles == null)
return false;
if(map.Information.RootContentFolder == "")
return false;
if(map.Infomation.Rows == 0)
return false;
if(map.Infomation.TileSize == 0)
return false;
}

public Foo()
{
if(fileDetails.ToString() == string.Empty)
return Common.ReturnResult.Failed;
if(map == null)
return Common.ReturnResult.Failed;
if(!Success(map))
return Common.ReturnResult.Failed;
return Common.ReturnResult.OKorWhatever;

}

Can you change the map object? If so the Success Status is probably better off there as a property, you could also break this down into further sub-properties such as HasImages, HasInformation etc

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

[Dalek Dave]

May be better to use CASE statement.

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[Bernhard Hiller]

What about an "IValidable" interface defining a method "Validate()"? When "map" and its properties implement it, you could simply call map.Validate() which would encapsulate that logic there.

[venomation]

Thanks for the reply,the problem is that I would have allot of validation objects everywhere, which wouldn't be very fun to use...

[Matty22]

HOw about public bool CheckForNulls(object[] thingsThatShouldntBeNull) { return thingsThatShouldntBeNull.TrueForAll(x => x != null); } CheckForNulls(new object[]{dumbshitCoderField1,dumbShitCoderField2);