Check iReveal, a combination of NMS and SIEM which I think can completely cater to all your needs.
- SNMP Support with Auto Discovery
iReveal performs Auto Discovery of hosts in a single subnet or in multiple subnets. Once the devices are discovered, they will be classified into Windows, Linux/Unix, Databases, Smartphones, LDAP supported devices and other categories. This classification is done based on the protocols (SNMP, WMI, SSH, TELNET and etc.,) available on those discovered devices.
- Ability to write code in .NET for checks, or creating “drivers” that would talk to equipment and translate the results to NMS.
Currently, iReveal uses C# code to perform auto discovery of devices, data accumulation from windows machines for Windows Resources (CPU, Memory, Disk Usage etc.,) and Windows Events using WMI protocol. This information is stored in the form of log files and they are given as input to various data repositories such as MySQL database and Solr search engine.Similarly, using C# we can implement code to communicate with the equipment and this information is stored in log files, which can be given as input to any system that accepts the log files as input.
- Rich graphical experience, with charts and trends, but also ability to create custom controls and views.
iReveal UI is mostly based on market leading technologies such as HTML5, Bootstrap and Angular JS which is rich in nature. We can also create custom views using Custom Dashboard feature where user can drag and drop the reports he/she wanted and they are dynamic in nature. User can resize the components within the custom dashboard and can re-arrange them as per their necessity.
- Syslog Analysis capability
iReveal has a built-in Syslog server which receives syslog packets forwarded from different devices such as Firewall, Router, Switch, Linux/Unix etc devices.
The syslog packets thus received are processed and analyzed. Different kind of analytical and trending reports are generated based on processed syslog information. Information such as Traffic (Bandwidth), Attacks, Virus, Security, Protocol Based Usage (Web, Mail, Telnet etc.,) and Traffic Trend reports.
- Is there a NMS System (even considering SCADA systems with support of SNMP) that is easy to extend using C#/VB.net and it has rich UI.
As mentioned earlier, iReveal uses C# to communicate with devices. iReveal uses generic(RFC) Management Information Base(s) (MIBs) to gather information from SNMP supported devices along with support for private MIB(s) that are vendor specific. iReveal can monitor any type of device that supports SNMP protocol.As SCADA (Supervisory Control And Data Acquisition) systems has support of SNMP, iReveal can monitor them and provide rich UI using HTML5, Bootstrap and Angular JS.
For more support details you can mail them at firstname.lastname@example.org