From af40d111039fd19b0bd980ce0ead5af78b4b6fdc Mon Sep 17 00:00:00 2001
From: soukoku <yinchun.wang@gmail.com>
Date: Tue, 15 Apr 2014 18:45:41 -0400
Subject: [PATCH] Fixed #5 for TWFix32 conversion exception in extension
 method.

---
 NTwain/TwainSessionExtensions.cs |  3 ++-
 NTwain/Values/ValueConverter.cs  | 17 ++++++++++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/NTwain/TwainSessionExtensions.cs b/NTwain/TwainSessionExtensions.cs
index b81e525..00044f3 100644
--- a/NTwain/TwainSessionExtensions.cs
+++ b/NTwain/TwainSessionExtensions.cs
@@ -372,7 +372,8 @@ namespace NTwain
         /// <returns></returns>
         public static IList<TWFix32> CapGetDPIs(this TwainSession session)
         {
-            return session.GetCapabilityValues(CapabilityId.ICapXResolution).Cast<TWFix32>().ToList();
+            var list = session.GetCapabilityValues(CapabilityId.ICapXResolution);
+            return list.Select(o => o.ConvertToFix32()).ToList();
         }
 
         /// <summary>
diff --git a/NTwain/Values/ValueConverter.cs b/NTwain/Values/ValueConverter.cs
index 3b08d17..a2921a9 100644
--- a/NTwain/Values/ValueConverter.cs
+++ b/NTwain/Values/ValueConverter.cs
@@ -1,4 +1,5 @@
-using System;
+using NTwain.Data;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -67,5 +68,19 @@ namespace NTwain.Values
         {
             return (ushort)(value >> 16);
         }
+
+        /// <summary>
+        /// Tries to convert to a value to <see cref="TWFix32"/> if possible.
+        /// </summary>
+        /// <param name="value">The value.</param>
+        /// <returns></returns>
+        public static TWFix32 ConvertToFix32(this object value)
+        {
+            if (value is TWFix32)
+            {
+                return (TWFix32)value;
+            }
+            return (TWFix32)Convert.ToSingle(value);
+        }
     }
 }