Windows上Jenkins声明式管道中的变量扩展

考虑以下管道：

pipeline {
/* continuous build pipeline for jenkins */
    agent any
    environment {
        /* initialize vairables for this job */
        path_msbuild = 'C:\\Program Files (x86)\\MSBuild\\14.0\\Bin\\msbuild.exe'
        path_workspace_root = 'C:\\Program Files (x86)\\Jenkins\\workspace\\MyApplication'
        path_solutionfile = '%path_workspace_root%\\MyApplication.sln' /* this variable doesn't expand */
        databasename = 'elements'
    }
    stages {
        stage ('solution') {
            steps {
                echo 'building solution'
                bat '"%path_msbuild%" "%path_solutionfile%" /p:Configuration=Release'
            }
        }
    }
}

此构建作业失败，因为％path_workspace_root％不会扩展，并且我收到一条错误消息，即找不到我要查找的文件。

我试过用双引号声明字符串：

pipeline {
/* continuous build pipeline for jenkins */
    agent any
    environment {
        /* initialize vairables for this job */
        path_msbuild = 'C:\\Program Files (x86)\\MSBuild\\14.0\\Bin\\msbuild.exe'
        path_workspace_root = 'C:\\Program Files (x86)\\Jenkins\\workspace\\MyApplication'
        path_solutionfile = "%path_workspace_root%\\MyApplication.sln" /* this variable still doesn't expand */
        databasename = 'elements'
    }
    stages {
        stage ('solution') {
            steps {
                echo 'building solution'
                bat '"%path_msbuild%" "%path_solutionfile%" /p:Configuration=Release'
            }
        }
    }
}

我也尝试过使用双引号和延迟的扩展语法：

pipeline {
/* continuous build pipeline for jenkins */
    agent any
    environment {
        /* initialize vairables for this job */
        path_msbuild = 'C:\\Program Files (x86)\\MSBuild\\14.0\\Bin\\msbuild.exe'
        path_workspace_root = 'C:\\Program Files (x86)\\Jenkins\\workspace\\MyApplication'
        path_solutionfile = "!path_workspace_root!\\MyApplication.sln" /* this variable still doesn't expand */
        databasename = 'elements'
    }
    stages {
        stage ('solution') {
            steps {
                echo 'building solution'
                bat '"%path_msbuild%" "%path_solutionfile%" /p:Configuration=Release'
            }
        }
    }
}

1. 使％path_workspace_root％变量正确扩展的正确语法是什么？
2. 我是在做这种“艰难的方式”吗（我是詹金斯的新手），有没有更简单的方法来完成我的工作？我想象随着管道的变大，我将需要设置许多这些环境变量。