### Another round on the ModelState percentage complete calculator

August 4, 2011

Update: The mathematics is wrong – not sure what I was thinking. See the updated version here.

So the prior version has a bug – it works fine if the scaling value is 50 however it fails at other values. Whoops! That has been fixed and now we have a MaxValue scaler too. The MaxValue scaler is useful if you want to calculate the percentage done as maxing out at say 91% because you want to manually calculate the remaining 9%.

```
public static class ModelStatePercentCompleteCalculator
{
// Very rough but reusable % complete calculator that is an extension so can be
// called simply as ModelState.PercentComplete() in a controller action. Iterates
// over the items in ModelState returns percentage complete where a complete field
// is seen as having no errors. If the ModelState.IsValid returns true, the
// model is 100% complete.
//
// ScalePercentWithValueAsZero: if you calculate the % done on a model and it says say 40%
// really it is 0% than set ScalePercentWithValueAsZero=40 and it'll treat 40% as 0% and
// scale it appropriately to 100 or maxValue
//
// MaxValue: if you want the maximum value to be less than 100 than set it here so you can
// accomodate calculating to 100% based on some other criteria too (which you're
// responsible for)
public static int PercentComplete(this ModelStateDictionary modelStateDictionary, int? ScalePercentWithValueAsZero = null, int? MaxValue = 100)
{
int totalItems = 0;
int validItems = 0;
int percentComplete = 0;
if (MaxValue.HasValue && (MaxValue.Value < 0 || MaxValue.Value > 100))
throw new ArgumentOutOfRangeException("MaxValue must between 0 and 100!");
if (modelStateDictionary.IsValid)
{
percentComplete = MaxValue.Value;
}
else
{
foreach (var item in modelStateDictionary)
{
totalItems++;
if (item.Value.Errors.Count == 0)
validItems++;
}
if (totalItems > 0)
percentComplete = (MaxValue.Value * validItems) / totalItems;
}
if (ScalePercentWithValueAsZero.HasValue && ScalePercentWithValueAsZero.Value > 0 && percentComplete >= ScalePercentWithValueAsZero)
{
percentComplete = (percentComplete - ScalePercentWithValueAsZero.Value) / (MaxValue.Value - ScalePercentWithValueAsZero.Value) * 100;
}
else
{
percentComplete = percentComplete / 100 * MaxValue.Value;
}
return percentComplete;
}
```

Categories:
ASP.NET MVC