diff --git a/codes/csharp/chapter_searching/binary_search_edge.cs b/codes/csharp/chapter_searching/binary_search_edge.cs
new file mode 100644
index 000000000..081cc6a11
--- /dev/null
+++ b/codes/csharp/chapter_searching/binary_search_edge.cs
@@ -0,0 +1,57 @@
+/**
+* File: binary_search_edge.cs
+* Created Time: 2023-06-01
+* Author: hpstory (hpstory1024@163.com)
+*/
+
+namespace hello_algo.chapter_searching; 
+
+public class binary_search_edge {
+    /* 二分查找最左一个元素 */
+    public static int binarySearchLeftEdge(int[] nums, int target) {
+        int i = 0, j = nums.Length - 1; // 初始化双闭区间 [0, n-1]
+        while (i <= j) {
+            int m = i + (j - i) / 2; // 计算中点索引 m
+            if (nums[m] < target)
+                i = m + 1; // target 在区间 [m+1, j] 中
+            else if (nums[m] > target)
+                j = m - 1; // target 在区间 [i, m-1] 中
+            else
+                j = m - 1; // 首个小于 target 的元素在区间 [i, m-1] 中
+        }
+        if (i == nums.Length || nums[i] != target)
+            return -1; // 未找到目标元素，返回 -1
+        return i;
+    }
+
+    /* 二分查找最右一个元素 */
+    public static int binarySearchRightEdge(int[] nums, int target) {
+        int i = 0, j = nums.Length - 1; // 初始化双闭区间 [0, n-1]
+        while (i <= j) {
+            int m = i + (j - i) / 2; // 计算中点索引 m
+            if (nums[m] < target)
+                i = m + 1; // target 在区间 [m+1, j] 中
+            else if (nums[m] > target)
+                j = m - 1; // target 在区间 [i, m-1] 中
+            else
+                i = m + 1; // 首个大于 target 的元素在区间 [m+1, j] 中
+        }
+        if (j < 0 || nums[j] != target)
+            return -1; // 未找到目标元素，返回 -1
+        return j;
+    }
+
+    [Test]
+    public void Test() {
+        int target = 6;
+        int[] nums = { 1, 3, 6, 6, 6, 6, 6, 10, 12, 15 };
+
+        // 二分查找最左一个元素
+        int indexLeft = binarySearchLeftEdge(nums, target);
+        Console.WriteLine("数组中最左一个元素 6 的索引 = " + indexLeft);
+
+        // 二分查找最右一个元素
+        int indexRight = binarySearchRightEdge(nums, target);
+        Console.WriteLine("数组中最右一个元素 6 的索引 = " + indexRight);
+    }
+}
diff --git a/codes/csharp/chapter_sorting/heap_sort.cs b/codes/csharp/chapter_sorting/heap_sort.cs
new file mode 100644
index 000000000..d6074faeb
--- /dev/null
+++ b/codes/csharp/chapter_sorting/heap_sort.cs
@@ -0,0 +1,52 @@
+/**
+* File: heap_sort.cs
+* Created Time: 2023-06-01
+* Author: hpstory (hpstory1024@163.com)
+*/
+
+namespace hello_algo.chapter_sorting; 
+
+public class heap_sort {
+    /* 堆的长度为 n ，从节点 i 开始，从顶至底堆化 */
+    public static void siftDown(int[] nums, int n, int i) {
+        while (true) {
+            // 判断节点 i, l, r 中值最大的节点，记为 ma
+            int l = 2 * i + 1;
+            int r = 2 * i + 2;
+            int ma = i;
+            if (l < n && nums[l] > nums[ma])
+                ma = l;
+            if (r < n && nums[r] > nums[ma])
+                ma = r;
+            // 若节点 i 最大或索引 l, r 越界，则无需继续堆化，跳出
+            if (ma == i)
+                break;
+            // 交换两节点
+            (nums[ma], nums[i]) = (nums[i], nums[ma]);
+            // 循环向下堆化
+            i = ma;
+        }
+    }
+
+    /* 堆排序 */
+    public static void heapSort(int[] nums) {
+        // 建堆操作：堆化除叶节点以外的其他所有节点
+        for (int i = nums.Length / 2 - 1; i >= 0; i--) {
+            siftDown(nums, nums.Length, i);
+        }
+        // 从堆中提取最大元素，循环 n-1 轮
+        for (int i = nums.Length - 1; i > 0; i--) {
+            // 交换根节点与最右叶节点（即交换首元素与尾元素）
+            (nums[i], nums[0]) = (nums[0], nums[i]);
+            // 以根节点为起点，从顶至底进行堆化
+            siftDown(nums, i, 0);
+        }
+    }
+
+    [Test]
+    public void Test() {
+        int[] nums = { 4, 1, 3, 1, 5, 2 };
+        heapSort(nums);
+        Console.WriteLine("堆排序完成后 nums = " + string.Join(" ", nums));
+    }
+}
diff --git a/codes/csharp/chapter_sorting/selection_sort.cs b/codes/csharp/chapter_sorting/selection_sort.cs
new file mode 100644
index 000000000..42550494b
--- /dev/null
+++ b/codes/csharp/chapter_sorting/selection_sort.cs
@@ -0,0 +1,32 @@
+/**
+* File: selection_sort.cs
+* Created Time: 2023-06-01
+* Author: hpstory (hpstory1024@163.com)
+*/
+
+namespace hello_algo.chapter_sorting;
+
+public class selection_sort {
+    /* 选择排序 */
+    public static void selectionSort(int[] nums) {
+        int n = nums.Length;
+        // 外循环：未排序区间为 [i, n-1]
+        for (int i = 0; i < n - 1; i++) {
+            // 内循环：找到未排序区间内的最小元素
+            int k = i;
+            for (int j = i + 1; j < n; j++) {
+                if (nums[j] < nums[k])
+                    k = j; // 记录最小元素的索引
+            }
+            // 将该最小元素与未排序区间的首个元素交换
+            (nums[k], nums[i]) = (nums[i], nums[k]);
+        }
+    }
+
+    [Test]
+    public void Test() {
+        int[] nums = { 4, 1, 3, 1, 5, 2 };
+        selectionSort(nums);
+        Console.WriteLine("选择排序完成后 nums = " + string.Join(" ", nums));
+    }
+}