Обход графа в глубину - C#

string [,]graph = new string[10,11];
            graph[0, 0] = "a";
            graph[0, 1] = "0"; //а
            graph[0, 2] = "b";//b
            graph[0, 3] = "c";//c
            graph[0, 4] = "0";//d
            graph[0, 5] = "0";//f
            graph[0, 6] = "0";//g
            graph[0, 7] = "0";//h
            graph[0, 8] = "0";//r
            graph[0, 9] = "0";//o
            graph[0, 10] = "0";//p
 
             graph[1, 0] = "b";
            graph[1, 1] = "a"; //а
            graph[1, 2] = "0";//b
            graph[1, 3] = "c";//c
            graph[1, 4] = "d";//d
            graph[1, 5] = "f";//f
            graph[1, 6] = "0";//g
            graph[1, 7] = "0";//h
            graph[1, 8] = "0";//r
            graph[1, 9] = "0";//o
            graph[1, 10] = "0";//p
 
            graph[2, 0] = "c";
            graph[2, 1] = "a"; //а
            graph[2, 2] = "b";//b
            graph[2, 3] = "0";//c
            graph[2, 4] = "0";//d
            graph[2, 5] = "f";//f
            graph[2, 6] = "0";//g
            graph[2, 7] = "0";//h
            graph[2, 8] = "0";//r
            graph[2, 9] = "0";//o
            graph[2, 10] = "0";//p
 
             graph[3, 0] = "d";
            graph[3, 1] = "0"; //а
            graph[3, 2] = "b";//b
            graph[3, 3] = "0";//c
            graph[3, 4] = "0";//d
            graph[3, 5] = "f";//f
            graph[3, 6] = "g";//g
            graph[3, 7] = "0";//h
            graph[3, 8] = "0";//r
            graph[3, 9] = "0";//o
            graph[3, 10] = "0";//p

             graph[4, 0] = "f";
            graph[4, 1] = "0"; //а
            graph[4, 2] = "b";//b
            graph[4, 3] = "c";//c
            graph[4, 4] = "d";//d
            graph[4, 5] = "0";//f
            graph[4, 6] = "0";//g
            graph[4, 7] = "0";//h
            graph[4, 8] = "0";//r
            graph[4, 9] = "0";//o
            graph[4, 10] = "0";//p
 
            graph[5, 0] = "g";
            graph[5, 1] = "0"; //а
            graph[5, 2] = "0";//b
            graph[5, 3] = "0";//c
            graph[5, 4] = "d";//d
            graph[5, 5] = "0";//f
            graph[5, 6] = "0";//g
            graph[5, 7] = "h";//h
            graph[5, 8] = "r";//r
            graph[5, 9] = "0";//o
            graph[5, 10] = "0";//p

            graph[6, 0] = "h";
            graph[6, 1] = "0"; //а
            graph[6, 2] = "0";//b
            graph[6, 3] = "0";//c
            graph[6, 4] = "0";//d
            graph[6, 5] = "0";//f
            graph[6, 6] = "g";//g
            graph[6, 7] = "0";//h
            graph[6, 8] = "r";//r
            graph[6, 9] = "0";//o
            graph[6, 10] = "0";//p
 
            graph[7, 0] = "r";
            graph[7, 1] = "0"; //а
            graph[7, 2] = "0";//b
            graph[7, 3] = "0";//c
            graph[7, 4] = "0";//d
            graph[7, 5] = "0";//f
            graph[7, 6] = "g";//g
            graph[7, 7] = "h";//h
            graph[7, 8] = "0";//r
            graph[7, 9] = "o";//o
            graph[7, 10] = "p";//p
 
            graph[8, 0] = "o";
            graph[8, 1] = "0"; //а
            graph[8, 2] = "0";//b
            graph[8, 3] = "0";//c
            graph[8, 4] = "0";//d
            graph[8, 5] = "0";//f
            graph[8, 6] = "0";//g
            graph[8, 7] = "0";//h
            graph[8, 8] = "r";//r
            graph[8, 9] = "0";//o
            graph[8, 10] = "p";//p
 
            graph[9, 0] = "p";
            graph[9, 1] = "0"; //а
            graph[9, 2] = "0";//b
            graph[9, 3] = "0";//c
            graph[9, 4] = "0";//d
            graph[9, 5] = "0";//f
            graph[9, 6] = "0";//g
            graph[9, 7] = "0";//h
            graph[9, 8] = "r";//r
            graph[9, 9] = "o";//o
            graph[9, 10] = "0";//p
            int n = 0;
            string zabor = "";
            string verh = "";
            string bfs_num = "";
            string vmist = "";
            string start = "";

            textBox3.Text = "Внршина        BFS-номер        Черга";
            start = Convert.ToString(textBox1.Text);
            for (int i = 0; i <= 9; i++)
            {
                if (graph[i, 0] == start)
                {
                    n++;        //номер DFS
                    verh = graph[i, 0];     //зберігаємо імя початкової вершини
                    bfs_num = Convert.ToString(n);      //dfs для виведення
                    vmist += graph[i, 0]; // стек
                    buf_i = i;  //до якого елементу відноситься
                    zabor += verh;// в стрічку добавляєм нову заборонену вершину
                }
            }
            textBox3.Text += Environment.NewLine + "      " + verh + "                    " + bfs_num + "                       " + vmist;
            while (vmist != "")
            {
 
                for (int i = buf_i, j = 1; j < 9; j++)
                {
                    if (graph[i, j] != "0")
                    {
                        if (zabor.Contains(graph[i, j]) == false)
                        {
                            n++;
                            verh = graph[i, j];
                            bfs_num = Convert.ToString(n);
                            vmist += graph[i, j];
                            textBox3.Text += Environment.NewLine + "      " + verh + "                    " + bfs_num + "                       " + vmist;
                            buf_i = j;
                            zabor += verh;
                        }
                        else
                        {
 
                            vmist = vmist.Substring(0,vmist.Length - 1);
                            buf_i = j;
                           /* int len = vmist.Length;
                            start =Convert.ToString(vmist[len]);
                            for (int k = 0; k <= 9; k++)
                            {
                                if (graph[k, 0] == start)
                                {
                                    buf_i = i;  //до якого елементу відноситься
                                }
                            }
                            */
                            textBox3.Text += Environment.NewLine + "      " + "-" + "                    " + "-"+ "                       " + vmist;
                        }
                    }
                }
 
            }