您可以尝试在csproj文件中添加以下行：

<UseWPF>true</UseWPF>

此行指示生成系统合并WPF目标，这是创建XAML文件所必需的。

• 我已经成功地构建了XAML WPF应用程序，请参考下面：-*
  My yaml code to build XAML WPF app with dotnet build：-

trigger:
- main

pool:
  vmImage: 'windows-latest'

variables:
  solution: '**/*.sln'
  buildPlatform: 'Any CPU'
  buildConfiguration: 'Release'

steps:
- task: UseDotNet@2
  inputs:
    packageType: 'sdk'
    version: '3.x'
- task: DotNetCoreCLI@2
  inputs:
    command: 'build'
    projects: '$(solution)'
    arguments: '--configuration $(buildConfiguration)'

输出：-

此外，作为替代方案，* 而不是dotnetbuild尝试使用VsBuild来构建管道 * 如下所示：-

trigger:
- master

pool:
  vmImage: 'windows-latest'

variables:
  solution: '**/*.sln'
  buildPlatform: 'Any CPU'
  buildConfiguration: 'Release'

steps:
- task: NuGetToolInstaller@1

- task: NuGetCommand@2
  inputs:
    restoreSolution: '$(solution)'

- task: VSBuild@1
  inputs:
    solution: '$(solution)'
    platform: '$(buildPlatform)'
    configuration: '$(buildConfiguration)'

- task: VSTest@2
  inputs:
    platform: '$(buildPlatform)'
    configuration: '$(buildConfiguration)'

输出：-