SharpDevelop5.1支持.net4.5.2以上版本

SharpDevelop5.1最高支持4.5.2（发布时的最高版本）

修改源码：

\SharpDevelop_5.1.0.5216_Source\src\Main\Base\Project\Util\Versions.cs
    static class Versions
    {
        public static readonly Version V2_0 = new Version(2, 0);
        public static readonly Version V3_0 = new Version(3, 0);
        public static readonly Version V3_5 = new Version(3, 5);
        public static readonly Version V4_0 = new Version(4, 0);
        public static readonly Version V4_5 = new Version(4, 5);
        public static readonly Version V4_5_1 = new Version(4, 5, 1);
        public static readonly Version V4_5_2 = new Version(4, 5, 2);
        public static readonly Version V4_6 = new Version(4, 6);
        public static readonly Version V4_6_1 = new Version(4, 6, 1);
        public static readonly Version V4_6_2 = new Version(4, 6, 2);
    }
SharpDevelop_5.1.0.5216_Source\src\Main\Base\Project\Project\TargetFrameworks\TargetFramework.cs
    public abstract class TargetFramework
    {
        public static readonly TargetFramework Net20 = new DotNet20();
        public static readonly TargetFramework Net30 = new DotNet30();
        public static readonly TargetFramework Net35 = new DotNet35();
        public static readonly TargetFramework Net35Client = new DotNet35Client();
        public static readonly TargetFramework Net40 = new DotNet4x(Versions.V4_0, RedistLists.Net40, DotnetDetection.IsDotnet40Installed);
        public static readonly TargetFramework Net40Client = new DotNet4xClient(Versions.V4_0, RedistLists.Net40Client, DotnetDetection.IsDotnet40Installed);
        public static readonly TargetFramework Net45 = new DotNet4x(Versions.V4_5, RedistLists.Net45, DotnetDetection.IsDotnet45Installed);
        public static readonly TargetFramework Net451 = new DotNet4x(Versions.V4_5_1, RedistLists.Net45, DotnetDetection.IsDotnet451Installed);
        public static readonly TargetFramework Net452 = new DotNet4x(Versions.V4_5_2, RedistLists.Net45, DotnetDetection.IsDotnet452Installed);
        public static readonly TargetFramework Net46 = new DotNet4x(Versions.V4_6, RedistLists.Net45, DotnetDetection.IsDotnet452Installed);
        public static readonly TargetFramework Net461 = new DotNet4x(Versions.V4_6_1, RedistLists.Net45, DotnetDetection.IsDotnet452Installed);
        public static readonly TargetFramework Net462 = new DotNet4x(Versions.V4_6_2, RedistLists.Net45, DotnetDetection.IsDotnet452Installed);
\SharpDevelop_5.1.0.5216_Source\src\Main\Base\Project\ICSharpCode.SharpDevelop.addin
    <Path name = "/SharpDevelop/TargetFrameworks">
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net20" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net30" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net35" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net35Client" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net40" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net40Client" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net45" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net451" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net452" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net46" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net461" />
        <Static class="ICSharpCode.SharpDevelop.Project.TargetFramework" member="Net462" />
    </Path>