How to open an .rdl file in Visual Studio?

For opening RDL file in designer make sure you have " Microsoft Reporting Services Projects" Installed.

Refer this : https://marketplace.visualstudio.com/items?itemName=ProBITools.MicrosoftReportProjectsforVisualStudio

Correct, the Report Definition Language is just XML. And, as with any other file, you can just open it (File/Open/File...) in Visual Studio, just like in a text editor. In order to see a designer you need to give Visual Studio a bit of context about what sort of file it is by making it part of a Report Server Project.

• Install SSDT for Visual Studio if you haven't already done so
• Create a new project using the 'Report Server Project' template
• Copy/move the .rdl file(s) you have into the folder for the newly created project (eg ..\Visual Studio 2015\Projects\My Report Project\My Report Project)
• Use the "Add Existing Item..." context menu option in Solution Explorer to add the .rdl to the project
• Open report designer by double-clicking the newly added report project item(s)