Validation attribute for testing a data is later than another

DateGreaterThanAttribute.cs

[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class DateGreaterThanAttribute : ValidationAttribute, IClientValidatable
{
    private const string DefaultErrorMessageFormatString = "The {0} field is required.";
    public string OtherProperty { get; private set; }

    public DateGreaterThanAttribute(string otherProperty)
    {
        if (string.IsNullOrEmpty(otherProperty))
        {
            throw new ArgumentNullException("otherProperty");
        }

        OtherProperty = otherProperty;
    }
    public override string FormatErrorMessage(string name)
    {
        return string.Format(ErrorMessageString, name, OtherProperty);
    }
    
    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        //Get PropertyInfo Object && Get Value of the property
        var basePropertyInfo = validationContext.ObjectType.GetProperty(OtherProperty);
        var basePropertyValue = basePropertyInfo.GetValue(validationContext.ObjectInstance, null);
        
        if(value == null || basePropertyValue == null)
        {
            return null;
        }
        DateTime startDate = new DateTime();
        DateTime thisDate = new DateTime();
        try
        {
            startDate = (DateTime)basePropertyValue;
            thisDate = (DateTime)value;
        }
        catch(Exception e)
        {
            var startSplit = basePropertyValue.ToString().Split('/');
            startDate = new DateTime(Convert.ToInt32(startSplit[2]), Convert.ToInt32(startSplit[1]), Convert.ToInt32(startSplit[0]));
            var thisSplit = value.ToString().Split('/');
            thisDate = new DateTime(Convert.ToInt32(thisSplit[2]), Convert.ToInt32(thisSplit[1]), Convert.ToInt32(thisSplit[0]));
        }

        //Actual comparision
        if (thisDate <= startDate)
        {
            var message = FormatErrorMessage(validationContext.DisplayName);
            return new ValidationResult(message);
        }

        //Default return - This means there were no validation error
        return null;
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        var rule = new ModelClientValidationRule();
        rule.ErrorMessage = FormatErrorMessage(metadata.GetDisplayName());

        //This string identifies which Javascript function to be executed to validate this 
        rule.ValidationType = "dategreaterthan";
        rule.ValidationParameters.Add("other", OtherProperty);
        yield return rule;
    }
}