WiX安装调用自定义DLL崩溃问题排查（DLL未打包进MSI）

问题场景 #

使用WiX制作安装包时，通过自定义DLL实现写入TXT文件的功能，已在product.wxs中配置自定义动作与DLL引用，DLL实现了WriteToFile方法，且所有项目平台均设置为32位，但安装程序运行时崩溃，排查发现输出的MSI中未包含该自定义DLL。

解决方案 #

• 修正DLL路径与文件名匹配
  当前product.wxs中<Binary>元素引用的DLL名为GetPathFromWizard.dll，但自定义DLL项目的命名是CustomActionLibrary，存在名称不匹配问题。需将SourceFile修改为实际的DLL文件名及正确路径，建议使用解决方案内的相对路径：

  <Binary Id="CustomActionsDLL" SourceFile="..\CustomActionLibrary\bin\x86\Release\CustomActionLibrary.dll" />
  

  替换路径为你的DLL项目实际输出目录。

• 确认DLL编译配置
  右键自定义DLL项目→属性→生成→平台目标设置为x86，确保编译后在输出目录生成32位DLL，且WiX项目引用的路径指向该输出文件。

• 将DLL添加到WiX项目引用
  在WiX项目中右键选择「添加→现有项」，将自定义DLL添加到项目中，此时SourceFile可直接使用项目内相对路径，避免编译时WiX无法定位文件。

• 检查WiX编译日志
  执行WiX编译命令时查看输出日志，排查是否存在「找不到指定DLL」的警告或错误：

  candle.exe product.wxs -ext WixUIExtension -ext WixUtilExtension
  light.exe product.wixobj -ext WixUIExtension -ext WixUtilExtension -out LocalService.msi
  

  若日志中有路径相关错误，需调整SourceFile路径至正确位置。

相关代码参考 #

product.wxs（修正后关键片段）

<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
    <Product Id="*" Name="Local Service" Language="1033" Version="0.0.0.3" Manufacturer="innomotion media GmbH" UpgradeCode="81cf2ed4-78b3-42c3-8e6a-cfda143f2133">
        <Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine" Platform="x86" />
        <MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed." />
        <MediaTemplate EmbedCab="yes" />

        <Feature Id="ProductFeature" Title="Local Service" Level="1">
            <ComponentGroupRef Id="ProductComponents" />
            <ComponentRef Id="AutoStartComponent" />
        </Feature>

        <InstallExecuteSequence>
            <Custom Action="SetCustomActionData" Before="RunWriteToFile">NOT Installed</Custom>
            <Custom Action="RunWriteToFile" After="InstallFiles">NOT Installed</Custom>
            <Custom Action="ShowSuccessMessage" After="InstallFinalize">NOT Installed</Custom>
        </InstallExecuteSequence>
    </Product>

    <Fragment>
        <Property Id="USER_URL" Value="http://default.url" />

        <Directory Id="TARGETDIR" Name="SourceDir">
            <Directory Id="ProgramFilesFolder">
                <Directory Id="INSTALLFOLDER" Name="LocalService" />
            </Directory>
        </Directory>

        <!-- 修正后的DLL引用路径 -->
        <Binary Id="CustomActionsDLL" SourceFile="..\CustomActionLibrary\bin\x86\Release\CustomActionLibrary.dll" />

        <CustomAction Id="SetCustomActionData"
                      Property="RunWriteToFile"
                      Value="USER_URL=[USER_URL]"
                      Execute="immediate" />

        <CustomAction Id="RunWriteToFile"
                      BinaryKey="CustomActionsDLL"
                      DllEntry="WriteToFile"
                      Execute="deferred"
                      Impersonate="no" />

        <CustomAction Id="ShowSuccessMessage" Execute="immediate" Return="ignore" Script="vbscript">
            <![CDATA[
            MsgBox "Installation completed successfully!" & vbCrLf & vbCrLf & _
                   "The program should be available under:" & vbCrLf & vbCrLf & _
                   "'C:\Program Files (x86)\LocalService\Navcon\net8.0\win-x64'." & vbCrLf & vbCrLf & _
                   "There, RUN AS ADMINISTRATOR (important): 'NAV.LocalService.Function.exe' to run the function app." & vbCrLf & vbCrLf & _
                   "Make sure to configure the 'local.settings.json' file as well from that folder.", _
                   vbInformation, "Installation Success"
            ]]>
        </CustomAction>
    </Fragment>

    <Fragment>
        <Component Id="AutoStartComponent" Guid="9f5f7e62-4e3d-4c0f-a5ab-3d2b17b6b1f8" Directory="INSTALLFOLDER">
            <RegistryValue Root="HKCU" Key="Software\Microsoft\Windows\CurrentVersion\Run"
                           Name="LocalService" Value="[INSTALLFOLDER]Navcon\net8.0\win-x64\NAV.LocalService.Function.exe"
                           Type="string" />
        </Component>
    </Fragment>
</Wix>

自定义DLL代码

namespace CustomActionLibrary
{
    public class CustomActions
    {
        [CustomAction]
        public static ActionResult WriteToFile(Session session)
        {
            try
            {
                string userUrl = session.CustomActionData["USER_URL"];
                string filePath = @"C:\UserUrl.txt";

                if (string.IsNullOrEmpty(userUrl)) 
                { 
                    userUrl = "nix";
                }
                
                File.WriteAllText(filePath, userUrl);
                session.Log($"Successfully wrote USER_URL ({userUrl}) to {filePath}");

                return ActionResult.Success;
            }
            catch (Exception ex)
            {
                session.Log($"Error writing to file: {ex.Message}");
                return ActionResult.Failure;
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者innom