A SQL Server technology that supports the creation, management, and delivery of both traditional, paper-oriented reports and interactive, web-based reports.
The behavior is caused by how the new WebForms Report Viewer (v15.x NuGet control) renders its HTML/toolbar in modern browsers, not by the ASP.NET configuration shown. The export dropdown is part of the built‑in HTML viewer toolbar and its appearance is controlled by the control’s own CSS and the page’s global styles.
The HTML viewer toolbar (including the export menu) is not directly customizable from the Report Viewer properties; only which actions/formats appear can be changed. Styling such as the dropdown background is inherited from the page and any global CSS. When upgrading from the legacy v10 control to the v15 NuGet control, existing site CSS can conflict with the new markup and cause effects like a transparent menu background.
To correct the invisible export dropdown background:
- Keep using the v15 WebForms NuGet package and the existing web.config/handler configuration (those are already correct for 15.0.0.0).
- Add CSS on the page (or in a site stylesheet) that targets the dropdown elements rendered by the toolbar and explicitly sets a background color and text color. For example, add a rule that applies to the menu items inside the Report Viewer area and sets
background-colorandcolorto appropriate values. - Ensure no global CSS rule (for example, a rule that sets
background-color: transparenton allli,a, orselectelements) overrides the Report Viewer’s menu styling. If such a rule exists, scope it away from the Report Viewer container or override it with more specific selectors for the Report Viewer.
If the toolbar itself is not required, another option is to hide the built‑in toolbar and provide custom export UI, but the standard toolbar’s look and feel (including the dropdown) cannot be changed from the control properties alone.
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