请结合初中知识点完成这道题的解析讲解视频---**Extracted Content:**
**Question Stem:**
已知: 如图1所示, △ABC中, ∠C = 90°, AC = BC, AD = DB, AE = CF。
**To Prove:**
求证: DE = DF
**Chart Description:**
* **Type:** Geometric figure, specifically a right-angled isosceles triangle.
* **Main Elements:**
* **Points:** A, B, C, D, E, F.
* **Lines/Segments:**
* Triangle ABC with sides AC, BC, AB.
* Point E is on AC.
* Point F is on BC.
* Point D is on AB.
* Line segment DE connects E and D.
* Line segment DF connects D and F.
* A dashed line segment CD connects C and D.
* **Shapes:** A large right-angled triangle labeled ABC.
* **Labels and Annotations:** The vertices of the triangle are labeled A, B, C. Points on the sides are labeled E, F, D. The diagram is captioned "图1" (Figure 1) below the drawing.
* **Relative Position:** Point C is the vertex of the right angle. AC is the vertical leg, and BC is the horizontal leg. A is above C, B is to the right of C. E is located on AC, between A and C. F is located on BC, between C and B. D is located on the hypotenuse AB, between A and B.