DRY! GenericComparer for sorting Generic Lists
I'm a pretty firm believer in the Ruby/Ruby on Rails idea of DRY ("Don't Repeat Yourself").
That said, I get pretty tired of writing comparers for sorting lists and generic lists. Every one of these comparers is exactly the same: you specify a list of properties related to the object and a sort direction, then call compare on those properties.
This can be changed with a little reflection:
public class GenericComparer<T> : IComparer<T>
{
public string SortExpression { get; set; }
public int SortDirection { get; set; } // 0:Ascending, 1:Descending
public GenericComparer(string sortExpression, int sortDirection)
{
this.SortExpression = sortExpression;
this.SortDirection = sortDirection;
}
public GenericComparer() { }
#region IComparer<T> Members
public int Compare(T x, T y)
{
PropertyInfo propertyInfo = typeof(T).GetProperty(SortExpression);
IComparable obj1 = (IComparable)propertyInfo.GetValue(x, null);
IComparable obj2 = (IComparable)propertyInfo.GetValue(y, null);
if (SortDirection == 0)
{
return obj1.CompareTo(obj2);
}
else return obj2.CompareTo(obj1);
}
#endregion
}
This is a code snippet I love to have in my arsenal.
Here's how you use it:
List<MyObject> objectList = GetObjects(); /* from your repository or whatever */
objectList.Sort(new GenericComparer<MyObject>("ObjectPropertyName", (int)SortDirection.Descending));
dropdown.DataSource = objectList;
dropdown.DataBind();
Note that Sort returns void. This means you can't throw this to the right of a DataSource call. You'd have to call this, then call your DataSource/DataBind.
Oracle Exception: Could not load file or assembly ‘Oracle.DataAccess, Version=2.111.7.20…
Last week, I was having performance issues with my workstation. I was told to remove unused files and applications. I had previously installed ODAC 11g for the Oracle Data Providers. After realizing they were not backwards compatible with the Oracle10g providers we're using in production, I removed ODAC 11g using the Oracle Universal Installer. Apparently, that doesn't completely remove references to the 11g client or components.
After removing files and directories, I began receiving the following error when accessing an application locally:
Exception message: Could not load file or assembly 'Oracle.DataAccess, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
To see what Oracle libraries are installed in the GAC, I ran the following command from a Visual Studio command prompt:
gacutil /l | find /i "Oracle" > c:\Scripts\oracle.txt
This gave me the following list (note: Oracle 2.111.7.20 libraries are installed by ODAC 11g)
Oracle.DataAccess, Version=2.102.2.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86 Oracle.Management.Omo, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86 Oracle.VsDevTools, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86 Oracle.Web, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86 Policy.2.102.Oracle.DataAccess, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86 System.Data.OracleClient, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089, processorArchitecture=x86 Oracle.DataAccess, Version=1.102.2.20, Culture=neutral, PublicKeyToken=89b483f429c47342 Oracle.DataAccess, Version=1.102.3.0, Culture=neutral, PublicKeyToken=89b483f429c47342 Oracle.Management.Omo, Version=1.102.2.20, Culture=neutral, PublicKeyToken=89b483f429c47342 Oracle.VsDevTools, Version=1.102.2.20, Culture=neutral, PublicKeyToken=89b483f429c47342 Policy.1.102.Oracle.DataAccess, Version=1.102.3.0, Culture=neutral, PublicKeyToken=89b483f429c47342 Policy.10.1.Oracle.DataAccess, Version=1.102.3.0, Culture=neutral, PublicKeyToken=89b483f429c47342 Policy.10.2.Oracle.DataAccess, Version=1.102.3.0, Culture=neutral, PublicKeyToken=89b483f429c47342 Policy.9.2.Oracle.DataAccess, Version=1.102.3.0, Culture=neutral, PublicKeyToken=89b483f429c47342 System.Data.OracleClient, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
I have spent a week trying to figure out why these libraries wouldn't uninstall from the GAC and why I couldn't possibly remove them from the Oracle Universal Installer.
To manually uninstall these libraries, you'll have to run the following commands from a Visual Studio Command Prompt:
gacutil /u "Oracle.Management.Omo, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86" gacutil /u "Oracle.VsDevTools, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86" gacutil /u "Oracle.Web, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86" gacutil /u "Policy.2.102.Oracle.DataAccess, Version=2.111.7.20, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86"
Here's the part that got me: I installed ODT, not just ODAC. This comes with a number of add-ons for Visual Studio (including Health Monitoring and Profiling). So, you have to manually edit the machine.config to get everything completely removed.
So,
Edit C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\machine.config and remove all references from the above libraries.
After following these steps, I was finally able to load the application locally using the ODAC/ODP.NET libraries for Oracle 10g.
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