Is it necessary to put the SLR in a drying oven in a very humid place? Can you put it in the SLR bag?

No The inner container in the camera bag has strong hygroscopicity, and the optical lens of the camera and lens is easy to fog when it is put in the bag for a long time, which affects the luminous flux. Slight fogging doesn't matter much. It can be removed after being used in the sun for a period of time, but serious fogging is a precursor to mildew. You don't have to use a special drying oven to dry the sealed box. You can use a sealed plastic box or a sealed plastic bag. It is better to go to a photographic equipment store to buy color-changing silicone or electronic regeneration to absorb moisture, and you can know whether to replace silicone according to the color. It is not recommended to use desiccant in biscuits and other foods. This desiccant is disposable, and the appearance of the failed desiccant is difficult to distinguish. At the same time, desiccants that absorb enough water are more likely to breed mold.