MSB4086:试图进行数字比较 [英] MSB4086: A numeric comparison was attempted

问题描述

如果一个版本号大于另一个版本号，我的msbuild需要采取条件操作. 我已经尝试像下面这样编码，但是发现我得到了一个错误(也在下面).我在哪里弄错了?

My msbuild needs to take conditional action if one version number is greater than another. I've tried to code it like the following, but find I get an error (also below). Where have I gone wrong?

<?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003"
     DefaultTargets="Main"
     ToolsVersion="4.0">

  <UsingTask TaskName="CompareVersions" TaskFactory="CodeTaskFactory"     AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
    <ParameterGroup>
      <LeftHandSide Required="true"/>
      <RightHandSide Required="true"/>
      <Result ParameterType="System.Int32" Output="true"/>
    </ParameterGroup>
    <Task>
      <Code Type="Fragment" Language="cs">
        Version a = Version.Parse( LeftHandSide );
        Version b = Version.Parse( RightHandSide );
        Result = a.CompareTo(b);
      </Code>
    </Task>
  </UsingTask>

   <Target Name="Main">
    <CompareVersions LeftHandSide="3.7" RightHandSide="3.6">
      <Output ItemName="ComparisonResult" TaskParameter="Result"/>
    </CompareVersions>
    <Message Text="ComparisonResult=$(ComparisonResult)"></Message>
    <PropertyGroup>
      <Setting Condition="$(ComparisonResult) &lt; 0">true</Setting>
    </PropertyGroup>
    <Message Text="Setting=$(Setting)"></Message>
   </Target>

</Project>

---

S:\>msbuild test.proj Microsoft (R) Build Engine version
4.0.30319.18408 [Microsoft .NET Framework, version 4.0.30319.18408] Copyright (C) Microsoft Corporation. All rights reserved.

Build started 04/12/2013 15:26:38.
Project "S:\test.proj" on node 1 (default targets).
Main:
   ComparisonResult=
S:\test.proj(28,16): error MSB4086: A numeric comparison was attempted on "$(ComparisonResult)" that evaluates to "" instead of a number, in conditio n "$(ComparisonResult) < 0".
Done Building Project "S:\test.proj" (default targets) -- FAILED.


Build FAILED.

"S:\test.proj" (default target) (1) ->
(Main target) ->
S:\test.proj(28,16): error MSB4086: A numeric comparison was attempted on "$(ComparisonResult)" that evaluates to "" instead of a number, in condit ion "$(ComparisonResult) < 0".

   0 Warning(s)
   1 Error(s)

Time Elapsed 00:00:00.09

S:\>

推荐答案

好，笨拙.

<CompareVersions LeftHandSide="3.7" RightHandSide="3.6">
  <Output ItemName="ComparisonResult" TaskParameter="Result"/>
</CompareVersions>

应该是这样:

<CompareVersions LeftHandSide="3.7" RightHandSide="3.6">
  <Output PropertyName="ComparisonResult" TaskParameter="Result"/>
</CompareVersions>

PropertyName代替ItemName

PropertyName instead of ItemName

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