Concatenation Error in query in sqlserver

Hi below code shows error while concatening

string tour_Date = Convert.ToDateTime(tourdate).ToString("yyyy-MM-dd");

strCmd = @"create table #temp(dtime datetime)
declare @i int = 0, @date datetime ='"+tour_Date+"'
while @i < 4
begin
insert into #temp ([dtime]) values (dateadd(dd,@i,@date))
set @i = @i + 1
end

my requirement is i want to concatenate tour_Date with datetime

ie @date datetime ='"+tour_Date+"'.

i have tried @date datetime =+'&tour_Date&'+,

@date datetime ='+tour_Date+'. every thing shows error

how to solve this

Regards

Baiju

drop table #temp";