Thank you Eswari -
I can see now how to pass values on the query string.
But I do see many parameters being passed from the client that are not being picked up in the POST.
Example "GridRequestParams" is a key in the form being posted -
{"RequestType":9,"gridID":"GenericListGrid","PrimaryKeys":["Id"],"PrimaryKeyValues":["2"],"GridSaveMapper":"/Environments/Save","GridEditMode":"InlineForm"}
Example "ClientObject" is another key that is being posted -
{"AutoFormat":2,"AllowSorting":false,"AllowPaging":true,"AllowGrouping":false,"HttpRequestType":"post","ShowCaption":false,"ShowRowHeader":false,"VisibleColumns":[{"Name":"Id","Member":"Id","type":"Int32","HeaderText":"Id","FormatText":"","JqueryFormat":"","Visible":true,"CssName":null,"Width":-1,"AllowFilter":true,"IsUnbound":false,"cellEditType":0,"numericEditParams":null,"percentEditParams":null,"maskEditParams":null,"TemplateColumn":false,"TemplateName":null,"AllowEditing":true,"ResizeSettings":true,"TextAlign":0,"AllowAutoWrap":true,"AllowSearching":true,"AllowContextMenu":true,"AllowFormatinEditMode":false,"DropDownDataSource":null,"DataTextField":"","DataValueField":"","HtmlEncode":false,"IsNullable":false,"GridCommands":""},{"Name":"Name","Member":"Name","type":"String","HeaderText":"Name","FormatText":"","JqueryFormat":"","Visible":true,"CssName":null,"Width":-1,"AllowFilter":true,"IsUnbound":false,"cellEditType":0,"numericEditParams":null,"percentEditParams":null,"maskEditParams":null,"TemplateColumn":false,"TemplateName":null,"AllowEditing":true,"ResizeSettings":true,"TextAlign":0,"AllowAutoWrap":true,"AllowSearching":true,"AllowContextMenu":true,"AllowFormatinEditMode":false,"DropDownDataSource":null,"DataTextField":"","DataValueField":"","HtmlEncode":false,"IsNullable":false,"GridCommands":""},{"Name":"ExternalId","Member":"ExternalId","type":"Int32","HeaderText":"ExternalId","FormatText":"","JqueryFormat":"","Visible":true,"CssName":null,"Width":-1,"AllowFilter":true,"IsUnbound":false,"cellEditType":2,"numericEditParams":null,"percentEditParams":null,"maskEditParams":null,"TemplateColumn":false,"TemplateName":null,"AllowEditing":true,"ResizeSettings":true,"TextAlign":0,"AllowAutoWrap":true,"AllowSearching":true,"AllowContextMenu":true,"AllowFormatinEditMode":false,"DropDownDataSource":null,"DataTextField":"","DataValueField":"","HtmlEncode":false,"IsNullable":true,"GridCommands":""},{"Name":"ContactId","Member":"ContactId","type":"Int32","HeaderText":"ContactId","FormatText":"","JqueryFormat":"","Visible":true,"CssName":null,"Width":-1,"AllowFilter":true,"IsUnbound":false,"cellEditType":2,"numericEditParams":null,"percentEditParams":null,"maskEditParams":null,"TemplateColumn":false,"TemplateName":null,"AllowEditing":true,"ResizeSettings":true,"TextAlign":0,"AllowAutoWrap":true,"AllowSearching":true,"AllowContextMenu":true,"AllowFormatinEditMode":false,"DropDownDataSource":null,"DataTextField":"","DataValueField":"","HtmlEncode":false,"IsNullable":false,"GridCommands":""},{"Name":"AccountId","Member":"AccountId","type":"Int32","HeaderText":"AccountId","FormatText":"","JqueryFormat":"","Visible":true,"CssName":null,"Width":-1,"AllowFilter":true,"IsUnbound":false,"cellEditType":6,"numericEditParams":null,"percentEditParams":null,"maskEditParams":null,"TemplateColumn":false,"TemplateName":null,"AllowEditing":true,"ResizeSettings":true,"TextAlign":0,"AllowAutoWrap":true,"AllowSearching":true,"AllowContextMenu":true,"AllowFormatinEditMode":false,"DropDownDataSource":[{"Id":1,"ParentAccountId":null,"Name":"test","ExternalId":"1","Address":"qweqw ","City":"rere ","State":"tx ","Country":"yutryt ","Phone":"1231231234","Status":"1 ","Contacts":null,"Licenses":null,"Environments":null,"PrimaryKeyPropertyNames":["Id"]},{"Id":2,"ParentAccountId":1,"Name":"qweqweqw","ExternalId":null,"Address":null,"City":null,"State":null,"Country":null,"Phone":null,"Status":null,"Contacts":null,"Licenses":null,"Environments":null,"PrimaryKeyPropertyNames":["Id"]},{"Id":3,"ParentAccountId":null,"Name":"qweqwe","ExternalId":null,"Address":null,"City":null,"State":null,"Country":null,"Phone":null,"Status":null,"Contacts":null,"Licenses":null,"Environments":null,"PrimaryKeyPropertyNames":["Id"]}],"DataTextField":"Name","DataValueField":"Id","HtmlEncode":false,"IsNullable":false,"GridCommands":""},{"Name":"Contact","Member":"Contact","type":"","HeaderText":"Contact","FormatText":"<a rel='nofollow' href='Contacts?ContactId={Id}'>Contact</a>","JqueryFormat":"","Visible":true,"CssName":null,"Width":-1,"AllowFilter":true,"IsUnbound":true,"cellEditType":0,"numericEditParams":null,"percentEditParams":null,"maskEditParams":null,"TemplateColumn":false,"TemplateName":null,"AllowEditing":true,"ResizeSettings":true,"TextAlign":0,"AllowAutoWrap":true,"AllowSearching":true,"AllowContextMenu":true,"AllowFormatinEditMode":false,"DropDownDataSource":null,"DataTextField":"","DataValueField":"","HtmlEncode":false,"IsNullable":false,"GridCommands":""},{"Name":"Environment Versions","Member":"Environment Versions","type":"","HeaderText":"Environment Versions","FormatText":"<a rel='nofollow' href='EnvironmentVersions?EnvironmentVersionId={Id}'>Environment Versions</a>","JqueryFormat":"","Visible":true,"CssName":null,"Width":-1,"AllowFilter":true,"IsUnbound":true,"cellEditType":0,"numericEditParams":null,"percentEditParams":null,"maskEditParams":null,"TemplateColumn":false,"TemplateName":null,"AllowEditing":true,"ResizeSettings":true,"TextAlign":0,"AllowAutoWrap":true,"AllowSearching":true,"AllowContextMenu":true,"AllowFormatinEditMode":false,"DropDownDataSource":null,"DataTextField":"","DataValueField":"","HtmlEncode":false,"IsNullable":false,"GridCommands":""}],"PageSize":12,"CurrentIndex":0,"SearchHiddenColumn":false,"SearchType":8,"AllowDeleting":true,"GroupedColumns":[],"CaptionText":"{Caption} : {TotalRecordsCount} Items","TotalRecordsCount":3,"EnableOnDemand":false,"AllowSummaries":false,"CurrentPageNo":1,"AllowFiltering":true,"AllowFormatFiltering":false,"AllowCaseSensitive":true,"AllowFormatGrouping":false,"SortColumn":[],"SortDirection":[],"FilterConditions":[],"AllowEditing":true,"ResizeSettings":{"ResizeToFit":false,"ClipContent":false},"AllowAutoWrap":false,"ShowStackedHeader":false,"StackedColumns":[],"MergeCells":[],"StackedRows":[],"AllowSearching":false,"SearchConditions":[],"ChildGrid":"","AllowNew":true,"AllowAlternateRowStyle":false,"AllowMergeCells":false,"Culture":"en-US","FilterMode":"Default"}
All that data could be useful during a post, I'm still trying to determine the best way to get to it.