How to delete sub directory folder file in azure block blob storage in asp.net

See more:

C#

Azure

i have create directory on azure blob like
A is main directory A1,A2,A3 is a sub directories, i want to delete file from sub dirctories
example https://eventusblob1.blob.core.windows.net/maincontainer/A/A1/1.text

i want delete only 1.text how can do this in c#

please Help

What I have tried:

i have treid to delete file this method

blockBlob.Delete();
its delete hole blob