Problem with dynamically building LINQ queries for WMI

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LINQ

WMI

This is the current scenario.

I have a WPF form, where there's a combobox from where one can choose any of the Win 32 classes. Below that, I have a datagrid where one can put one of many of the properties.

For example, for Win32_Volume, one can put in the DeviceID, the DriveLetter, the SerialNumber, etc. They can fill up any number of the properties and then the application has to run a query testing if any object exists in the system matching the criterion/criteria.

Since the user is allowed to fill any number of the properties, I am having a hard time building the query.

What I have tried:

Here is what I have tried up till now.

I have built a dictionary with the propertyname as the key and the user-inputs as the value.

The code-behind is like this:

private ManagementObjectCollection GetObjectsOfClass(string classname)
        {            
            var objectcollection = new ManagementObjectSearcher("SELECT * FROM " + classname).Get();
            return objectcollection;
        }

        private ManagementObject GetObject(string classname, Dictionary<string,string> conditions)
        {
            var query = GetObjectsOfClass(classname).Cast<ManagementObject>();
            
            foreach(var condition in conditions)
            {
                query = query.Where(test => test.Properties[condition.Key].Value.ToString().Contains(condition.Value));                
            }

            return query.FirstOrDefault();
        }

GetObject takes the classname and the dictionary containing the Propertyname, value tuples. Then it gets all the instances of the class and then runs a LINQ query on them.

However this approach has a rather obnoxious code smell. What can I do to improve the code?