LINQ parameters, based on URL string --> ASP.net MVC4 C#

How can I make something like the
below "Create.cshtml" Desired work,
passing search criteria from the URL string ?
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Current

@model.MWR.Models.MAINT_WORK_REQ

...lots of "MAINT_WORK_REQ" database fields in code, then below....

                 @Html.DropDownList("ProjectID", new List<SelectListItem>
                 {
                    new SelectListItem{ Text="CST031 - LeftHand", Value = "CST031 - LeftHand" },
                    new SelectListItem{ Text="CST031 - RightHand", Value = "CST031 - RightHand" }
                 }
                 )

Select allOpen in new window

.......
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Desired

@model.MWR.Models.MAINT_WORK_REQ

...lots of "MAINT_WORK_REQ" database fields in code, then below....

                 @Html.DropDownListFor("ProjectID", new List<SelectListItem>
                 {
                    display all values from my existing C# 
                    GLOBAL "MWR.Models.Lookup_ProjectID" table
                        select ProjectID
                        from Lookup_ProjectID
                        where ProgramID = 'ABCcorp' // from URL string --> http://localhost:63802/ABCcorp/MAINT_WORK_REQ/Create
                        and active <> 0 // excludes inactive
                 }
                 )

Select allOpen in new window

.......