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Passing String parameter Value Through angular Service parameter Value is Automatically Appends Some Special Character
Here's my Angular controller
//Save And Update
$scope.AddUpdateBusinessType = function() {

    var businessType = {
        Code: $scope.businessCode,
        BusiType: $scope.businessType
    };

    var getBusinessTypeAction = $scope.BusinessTypeAction;

    if (getBusinessTypeAction == "Update") {
        businessType.BusinessTypeId = $scope.businessTypeId;
        var getBusinessTypeData = businessTypeService.updateBusinessType(businessType);
        getBusinessTypeData.then(function (msg) {
            GetAllBusinessType();
            $scope.ClearBusinessTypeForm();
            alert("Record Updated Successful");
            $scope.BusinessTypeAction = "";
            $scope.divBusinessType = false;
        }, function () {
            alert('Error in Updating Record');
        });
    } else {

**// Save Section**
            var getExistBusinessCode = businessTypeService.checkBusinessTypeCode(businessType.Code);
            getExistBusinessCode.then(function (businessTypeCode) {
                debugger;
                if (businessTypeCode == true) {
                    alert('Business Type Code Already Exist');
                } else {
                    debugger;
                    var getBusinessTypeData = businessTypeService.addBusinessType(businessType);
                    getBusinessTypeData.then(function (msg) {
                        GetAllBusinessType();
                        $scope.ClearBusinessTypeForm();
                        alert("Record Added Successful");
                        $scope.divBusinessType = false;
                    }, function () {
                        alert("Error Occured In Saving Data");
                    });
                }
            },function() {
                alert('Error Occured While Checking Records');
            });


        }
    }

In the above code Save Section I am trying to check if a value is exists in a database so I'm passing a string value to: checkBusinessTypeCode(businessType.Code) Service.When I Debug and See Value its Seems Normal.
Here's My Service:
//Check Business Code
this.checkBusinessTypeCode = function (businessTypeCode) {
    debugger;
    var response = $http({
        method: "post",
        url: "/BusinessType/CheckBusinessTypeDetailByCode",
        params: {
            businessTypeCode: JSON.stringify(businessTypeCode)
        }
    });
    return response;
}

But when Passing To Controller string value I get some unexpected behavior.
two \\ always appear automatically 
example 
"\"stringvalue\""

does the businessTypecode come into the service wrapped in quotes? If so, then JSON.stringify will escape those quotes before adding its own, which would explain why this happens.
JSON.stringify("hello") in a browser console gives ""hello"", which when you receive it over the wire, will look like "\"hello\"". That shouldn't be a problem as long as the receiving service is expecting to receive a string that reads literally "hello" as opposed to just hello

Is the issue resolved from your perspective, or are you still having problems?

I'm Still Having Above Problem
but as a quick solution i did code as follows
public bool _CheckBusinessTypeDetailByCode(string businessTypeCode)
    {
        string bisCode = businessTypeCode.Replace("\"", "");
        bool isExist;
        isExist = _IBusinessTypeRepository.IsExist(x => x.IsActive && !x.IsDelete && x.Code == bisCode);
        return isExist;
    }

I don't know is it bad practice or not , any way it is solved my problem.
Before did this modification 
 string businessTypeCode always gives value as 
"\"somevalue\""
