StringBuilder sb = new StringBuilder();
sb.AppendLine("Index = R, G, B");
Int16 i;
for (i = 0; i < 256; ++i ) {
// get color by index
Autodesk.AutoCAD.Colors.Color color =
Autodesk.AutoCAD.Colors.Color.FromColorIndex(AcCol.ColorMethod.None, i);
Byte r = color.Red;
Byte g = color.Green;
Byte b = color.Blue;
sb.AppendLine(String.Format("{0} = {1}, {2}, {3}", i, r, g, b));
}
String result = sb.ToString();
But I got strange result:Index = R, G, B
0 = 0, 0, 0
1 = 0, 0, 1
2 = 0, 0, 2
3 = 0, 0, 3
4 = 0, 0, 4
5 = 0, 0, 5
6 = 0, 0, 6
7 = 0, 0, 7
8 = 0, 0, 8
9 = 0, 0, 9
10 = 0, 0, 10
11 = 0, 0, 11
12 = 0, 0, 12
13 = 0, 0, 13
14 = 0, 0, 14
15 = 0, 0, 15
16 = 0, 0, 16
17 = 0, 0, 17
18 = 0, 0, 18
19 = 0, 0, 19
20 = 0, 0, 20
21 = 0, 0, 21
22 = 0, 0, 22
23 = 0, 0, 23
24 = 0, 0, 24
25 = 0, 0, 25
26 = 0, 0, 26
27 = 0, 0, 27
28 = 0, 0, 28
29 = 0, 0, 29
30 = 0, 0, 30
31 = 0, 0, 31
32 = 0, 0, 32
33 = 0, 0, 33
34 = 0, 0, 34
35 = 0, 0, 35
36 = 0, 0, 36
37 = 0, 0, 37
38 = 0, 0, 38
39 = 0, 0, 39
40 = 0, 0, 40
41 = 0, 0, 41
42 = 0, 0, 42
43 = 0, 0, 43
44 = 0, 0, 44
45 = 0, 0, 45
46 = 0, 0, 46
47 = 0, 0, 47
48 = 0, 0, 48
49 = 0, 0, 49
50 = 0, 0, 50
51 = 0, 0, 51
52 = 0, 0, 52
53 = 0, 0, 53
54 = 0, 0, 54
55 = 0, 0, 55
56 = 0, 0, 56
57 = 0, 0, 57
58 = 0, 0, 58
59 = 0, 0, 59
60 = 0, 0, 60
61 = 0, 0, 61
62 = 0, 0, 62
63 = 0, 0, 63
64 = 0, 0, 64
65 = 0, 0, 65
66 = 0, 0, 66
67 = 0, 0, 67
68 = 0, 0, 68
69 = 0, 0, 69
70 = 0, 0, 70
71 = 0, 0, 71
72 = 0, 0, 72
73 = 0, 0, 73
74 = 0, 0, 74
75 = 0, 0, 75
76 = 0, 0, 76
77 = 0, 0, 77
78 = 0, 0, 78
79 = 0, 0, 79
80 = 0, 0, 80
81 = 0, 0, 81
82 = 0, 0, 82
83 = 0, 0, 83
84 = 0, 0, 84
85 = 0, 0, 85
86 = 0, 0, 86
87 = 0, 0, 87
88 = 0, 0, 88
89 = 0, 0, 89
90 = 0, 0, 90
91 = 0, 0, 91
92 = 0, 0, 92
93 = 0, 0, 93
94 = 0, 0, 94
95 = 0, 0, 95
96 = 0, 0, 96
97 = 0, 0, 97
98 = 0, 0, 98
99 = 0, 0, 99
100 = 0, 0, 100
101 = 0, 0, 101
102 = 0, 0, 102
103 = 0, 0, 103
104 = 0, 0, 104
105 = 0, 0, 105
106 = 0, 0, 106
107 = 0, 0, 107
108 = 0, 0, 108
109 = 0, 0, 109
110 = 0, 0, 110
111 = 0, 0, 111
112 = 0, 0, 112
113 = 0, 0, 113
114 = 0, 0, 114
115 = 0, 0, 115
116 = 0, 0, 116
117 = 0, 0, 117
118 = 0, 0, 118
119 = 0, 0, 119
120 = 0, 0, 120
121 = 0, 0, 121
122 = 0, 0, 122
123 = 0, 0, 123
124 = 0, 0, 124
125 = 0, 0, 125
126 = 0, 0, 126
127 = 0, 0, 127
128 = 0, 0, 128
129 = 0, 0, 129
130 = 0, 0, 130
131 = 0, 0, 131
132 = 0, 0, 132
133 = 0, 0, 133
134 = 0, 0, 134
135 = 0, 0, 135
136 = 0, 0, 136
137 = 0, 0, 137
138 = 0, 0, 138
139 = 0, 0, 139
140 = 0, 0, 140
141 = 0, 0, 141
142 = 0, 0, 142
143 = 0, 0, 143
144 = 0, 0, 144
145 = 0, 0, 145
146 = 0, 0, 146
147 = 0, 0, 147
148 = 0, 0, 148
149 = 0, 0, 149
150 = 0, 0, 150
151 = 0, 0, 151
152 = 0, 0, 152
153 = 0, 0, 153
154 = 0, 0, 154
155 = 0, 0, 155
156 = 0, 0, 156
157 = 0, 0, 157
158 = 0, 0, 158
159 = 0, 0, 159
160 = 0, 0, 160
161 = 0, 0, 161
162 = 0, 0, 162
163 = 0, 0, 163
164 = 0, 0, 164
165 = 0, 0, 165
166 = 0, 0, 166
167 = 0, 0, 167
168 = 0, 0, 168
169 = 0, 0, 169
170 = 0, 0, 170
171 = 0, 0, 171
172 = 0, 0, 172
173 = 0, 0, 173
174 = 0, 0, 174
175 = 0, 0, 175
176 = 0, 0, 176
177 = 0, 0, 177
178 = 0, 0, 178
179 = 0, 0, 179
180 = 0, 0, 180
181 = 0, 0, 181
182 = 0, 0, 182
183 = 0, 0, 183
184 = 0, 0, 184
185 = 0, 0, 185
186 = 0, 0, 186
187 = 0, 0, 187
188 = 0, 0, 188
189 = 0, 0, 189
190 = 0, 0, 190
191 = 0, 0, 191
192 = 0, 0, 192
193 = 0, 0, 193
194 = 0, 0, 194
195 = 0, 0, 195
196 = 0, 0, 196
197 = 0, 0, 197
198 = 0, 0, 198
199 = 0, 0, 199
200 = 0, 0, 200
201 = 0, 0, 201
202 = 0, 0, 202
203 = 0, 0, 203
204 = 0, 0, 204
205 = 0, 0, 205
206 = 0, 0, 206
207 = 0, 0, 207
208 = 0, 0, 208
209 = 0, 0, 209
210 = 0, 0, 210
211 = 0, 0, 211
212 = 0, 0, 212
213 = 0, 0, 213
214 = 0, 0, 214
215 = 0, 0, 215
216 = 0, 0, 216
217 = 0, 0, 217
218 = 0, 0, 218
219 = 0, 0, 219
220 = 0, 0, 220
221 = 0, 0, 221
222 = 0, 0, 222
223 = 0, 0, 223
224 = 0, 0, 224
225 = 0, 0, 225
226 = 0, 0, 226
227 = 0, 0, 227
228 = 0, 0, 228
229 = 0, 0, 229
230 = 0, 0, 230
231 = 0, 0, 231
232 = 0, 0, 232
233 = 0, 0, 233
234 = 0, 0, 234
235 = 0, 0, 235
236 = 0, 0, 236
237 = 0, 0, 237
238 = 0, 0, 238
239 = 0, 0, 239
240 = 0, 0, 240
241 = 0, 0, 241
242 = 0, 0, 242
243 = 0, 0, 243
244 = 0, 0, 244
245 = 0, 0, 245
246 = 0, 0, 246
247 = 0, 0, 247
248 = 0, 0, 248
249 = 0, 0, 249
250 = 0, 0, 250
251 = 0, 0, 251
252 = 0, 0, 252
253 = 0, 0, 253
254 = 0, 0, 254
255 = 0, 0, 255
Index 1 = 255 0 0 (TrueColor: 16711680)
Index 2 = 255 255 0 (TrueColor: 16776960)
Index 3 = 0 255 0 (TrueColor: 65280)
Index 4 = 0 255 255 (TrueColor: 65535)
Index 5 = 0 0 255 (TrueColor: 255)
Index 6 = 255 0 255 (TrueColor: 16711935)
Index 7 = 255 255 255 (TrueColor: 16777215)
Index 8 = 128 128 128 (TrueColor: 8421504)
Index 9 = 192 192 192 (TrueColor: 12632256)
Index 10 = 255 0 0 (TrueColor: 16711680)
Index 11 = 255 127 127 (TrueColor: 16744319)
Index 12 = 165 0 0 (TrueColor: 10813440)
Index 13 = 165 82 82 (TrueColor: 10834514)
Index 14 = 127 0 0 (TrueColor: 8323072)
Index 15 = 127 63 63 (TrueColor: 8339263)
Index 16 = 76 0 0 (TrueColor: 4980736)
Index 17 = 76 38 38 (TrueColor: 4990502)
Index 18 = 38 0 0 (TrueColor: 2490368)
Index 19 = 38 19 19 (TrueColor: 2495251)
Index 20 = 255 63 0 (TrueColor: 16727808)
Index 21 = 255 159 127 (TrueColor: 16752511)
Index 22 = 165 41 0 (TrueColor: 10823936)
Index 23 = 165 103 82 (TrueColor: 10839890)
Index 24 = 127 31 0 (TrueColor: 8331008)
Index 25 = 127 79 63 (TrueColor: 8343359)
Index 26 = 76 19 0 (TrueColor: 4985600)
Index 27 = 76 47 38 (TrueColor: 4992806)
Index 28 = 38 9 0 (TrueColor: 2492672)
Index 29 = 38 23 19 (TrueColor: 2496275)
Index 30 = 255 127 0 (TrueColor: 16744192)
Index 31 = 255 191 127 (TrueColor: 16760703)
Index 32 = 165 82 0 (TrueColor: 10834432)
Index 33 = 165 124 82 (TrueColor: 10845266)
Index 34 = 127 63 0 (TrueColor: 8339200)
Index 35 = 127 95 63 (TrueColor: 8347455)
Index 36 = 76 38 0 (TrueColor: 4990464)
Index 37 = 76 57 38 (TrueColor: 4995366)
Index 38 = 38 19 0 (TrueColor: 2495232)
Index 39 = 38 28 19 (TrueColor: 2497555)
Index 40 = 255 191 0 (TrueColor: 16760576)
Index 41 = 255 223 127 (TrueColor: 16768895)
Index 42 = 165 124 0 (TrueColor: 10845184)
Index 43 = 165 145 82 (TrueColor: 10850642)
Index 44 = 127 95 0 (TrueColor: 8347392)
Index 45 = 127 111 63 (TrueColor: 8351551)
Index 46 = 76 57 0 (TrueColor: 4995328)
Index 47 = 76 66 38 (TrueColor: 4997670)
Index 48 = 38 28 0 (TrueColor: 2497536)
Index 49 = 38 33 19 (TrueColor: 2498835)
Index 50 = 255 255 0 (TrueColor: 16776960)
Index 51 = 255 255 127 (TrueColor: 16777087)
Index 52 = 165 165 0 (TrueColor: 10855680)
Index 53 = 165 165 82 (TrueColor: 10855762)
Index 54 = 127 127 0 (TrueColor: 8355584)
Index 55 = 127 127 63 (TrueColor: 8355647)
Index 56 = 76 76 0 (TrueColor: 5000192)
Index 57 = 76 76 38 (TrueColor: 5000230)
Index 58 = 38 38 0 (TrueColor: 2500096)
Index 59 = 38 38 19 (TrueColor: 2500115)
Index 60 = 191 255 0 (TrueColor: 12582656)
Index 61 = 223 255 127 (TrueColor: 14679935)
Index 62 = 124 165 0 (TrueColor: 8168704)
Index 63 = 145 165 82 (TrueColor: 9545042)
Index 64 = 95 127 0 (TrueColor: 6258432)
Index 65 = 111 127 63 (TrueColor: 7307071)
Index 66 = 57 76 0 (TrueColor: 3755008)
Index 67 = 66 76 38 (TrueColor: 4344870)
Index 68 = 28 38 0 (TrueColor: 1844736)
Index 69 = 33 38 19 (TrueColor: 2172435)
Index 70 = 127 255 0 (TrueColor: 8388352)
Index 71 = 191 255 127 (TrueColor: 12582783)
Index 72 = 82 165 0 (TrueColor: 5416192)
Index 73 = 124 165 82 (TrueColor: 8168786)
Index 74 = 63 127 0 (TrueColor: 4161280)
Index 75 = 95 127 63 (TrueColor: 6258495)
Index 76 = 38 76 0 (TrueColor: 2509824)
Index 77 = 57 76 38 (TrueColor: 3755046)
Index 78 = 19 38 0 (TrueColor: 1254912)
Index 79 = 28 38 19 (TrueColor: 1844755)
Index 80 = 63 255 0 (TrueColor: 4194048)
Index 81 = 159 255 127 (TrueColor: 10485631)
Index 82 = 41 165 0 (TrueColor: 2729216)
Index 83 = 103 165 82 (TrueColor: 6792530)
Index 84 = 31 127 0 (TrueColor: 2064128)
Index 85 = 79 127 63 (TrueColor: 5209919)
Index 86 = 19 76 0 (TrueColor: 1264640)
Index 87 = 47 76 38 (TrueColor: 3099686)
Index 88 = 9 38 0 (TrueColor: 599552)
Index 89 = 23 38 19 (TrueColor: 1517075)
Index 90 = 0 255 0 (TrueColor: 65280)
Index 91 = 127 255 127 (TrueColor: 8388479)
Index 92 = 0 165 0 (TrueColor: 42240)
Index 93 = 82 165 82 (TrueColor: 5416274)
Index 94 = 0 127 0 (TrueColor: 32512)
Index 95 = 63 127 63 (TrueColor: 4161343)
Index 96 = 0 76 0 (TrueColor: 19456)
Index 97 = 38 76 38 (TrueColor: 2509862)
Index 98 = 0 38 0 (TrueColor: 9728)
Index 99 = 19 38 19 (TrueColor: 1254931)
Index 100 = 0 255 63 (TrueColor: 65343)
Index 101 = 127 255 159 (TrueColor: 8388511)
Index 102 = 0 165 41 (TrueColor: 42281)
Index 103 = 82 165 103 (TrueColor: 5416295)
Index 104 = 0 127 31 (TrueColor: 32543)
Index 105 = 63 127 79 (TrueColor: 4161359)
Index 106 = 0 76 19 (TrueColor: 19475)
Index 107 = 38 76 47 (TrueColor: 2509871)
Index 108 = 0 38 9 (TrueColor: 9737)
Index 109 = 19 38 23 (TrueColor: 1254935)
Index 110 = 0 255 127 (TrueColor: 65407)
Index 111 = 127 255 191 (TrueColor: 8388543)
Index 112 = 0 165 82 (TrueColor: 42322)
Index 113 = 82 165 124 (TrueColor: 5416316)
Index 114 = 0 127 63 (TrueColor: 32575)
Index 115 = 63 127 95 (TrueColor: 4161375)
Index 116 = 0 76 38 (TrueColor: 19494)
Index 117 = 38 76 57 (TrueColor: 2509881)
Index 118 = 0 38 19 (TrueColor: 9747)
Index 119 = 19 38 28 (TrueColor: 1254940)
Index 120 = 0 255 191 (TrueColor: 65471)
Index 121 = 127 255 223 (TrueColor: 8388575)
Index 122 = 0 165 124 (TrueColor: 42364)
Index 123 = 82 165 145 (TrueColor: 5416337)
Index 124 = 0 127 95 (TrueColor: 32607)
Index 125 = 63 127 111 (TrueColor: 4161391)
Index 126 = 0 76 57 (TrueColor: 19513)
Index 127 = 38 76 66 (TrueColor: 2509890)
Index 128 = 0 38 28 (TrueColor: 9756)
Index 129 = 19 38 33 (TrueColor: 1254945)
Index 130 = 0 255 255 (TrueColor: 65535)
Index 131 = 127 255 255 (TrueColor: 8388607)
Index 132 = 0 165 165 (TrueColor: 42405)
Index 133 = 82 165 165 (TrueColor: 5416357)
Index 134 = 0 127 127 (TrueColor: 32639)
Index 135 = 63 127 127 (TrueColor: 4161407)
Index 136 = 0 76 76 (TrueColor: 19532)
Index 137 = 38 76 76 (TrueColor: 2509900)
Index 138 = 0 38 38 (TrueColor: 9766)
Index 139 = 19 38 38 (TrueColor: 1254950)
Index 140 = 0 191 255 (TrueColor: 49151)
Index 141 = 127 223 255 (TrueColor: 8380415)
Index 142 = 0 124 165 (TrueColor: 31909)
Index 143 = 82 145 165 (TrueColor: 5411237)
Index 144 = 0 95 127 (TrueColor: 24447)
Index 145 = 63 111 127 (TrueColor: 4157311)
Index 146 = 0 57 76 (TrueColor: 14668)
Index 147 = 38 66 76 (TrueColor: 2507340)
Index 148 = 0 28 38 (TrueColor: 7206)
Index 149 = 19 33 38 (TrueColor: 1253670)
Index 150 = 0 127 255 (TrueColor: 32767)
Index 151 = 127 191 255 (TrueColor: 8372223)
Index 152 = 0 82 165 (TrueColor: 21157)
Index 153 = 82 124 165 (TrueColor: 5405861)
Index 154 = 0 63 127 (TrueColor: 16255)
Index 155 = 63 95 127 (TrueColor: 4153215)
Index 156 = 0 38 76 (TrueColor: 9804)
Index 157 = 38 57 76 (TrueColor: 2505036)
Index 158 = 0 19 38 (TrueColor: 4902)
Index 159 = 19 28 38 (TrueColor: 1252390)
Index 160 = 0 63 255 (TrueColor: 16383)
Index 161 = 127 159 255 (TrueColor: 8364031)
Index 162 = 0 41 165 (TrueColor: 10661)
Index 163 = 82 103 165 (TrueColor: 5400485)
Index 164 = 0 31 127 (TrueColor: 8063)
Index 165 = 63 79 127 (TrueColor: 4149119)
Index 166 = 0 19 76 (TrueColor: 4940)
Index 167 = 38 47 76 (TrueColor: 2502476)
Index 168 = 0 9 38 (TrueColor: 2342)
Index 169 = 19 23 38 (TrueColor: 1251110)
Index 170 = 0 0 255 (TrueColor: 255)
Index 171 = 127 127 255 (TrueColor: 8355839)
Index 172 = 0 0 165 (TrueColor: 165)
Index 173 = 82 82 165 (TrueColor: 5395109)
Index 174 = 0 0 127 (TrueColor: 127)
Index 175 = 63 63 127 (TrueColor: 4145023)
Index 176 = 0 0 76 (TrueColor: 76)
Index 177 = 38 38 76 (TrueColor: 2500172)
Index 178 = 0 0 38 (TrueColor: 38)
Index 179 = 19 19 38 (TrueColor: 1250086)
Index 180 = 63 0 255 (TrueColor: 4129023)
Index 181 = 159 127 255 (TrueColor: 10452991)
Index 182 = 41 0 165 (TrueColor: 2687141)
Index 183 = 103 82 165 (TrueColor: 6771365)
Index 184 = 31 0 127 (TrueColor: 2031743)
Index 185 = 79 63 127 (TrueColor: 5193599)
Index 186 = 19 0 76 (TrueColor: 1245260)
Index 187 = 47 38 76 (TrueColor: 3089996)
Index 188 = 9 0 38 (TrueColor: 589862)
Index 189 = 23 19 38 (TrueColor: 1512230)
Index 190 = 127 0 255 (TrueColor: 8323327)
Index 191 = 191 127 255 (TrueColor: 12550143)
Index 192 = 82 0 165 (TrueColor: 5374117)
Index 193 = 124 82 165 (TrueColor: 8147621)
Index 194 = 63 0 127 (TrueColor: 4128895)
Index 195 = 95 63 127 (TrueColor: 6242175)
Index 196 = 38 0 76 (TrueColor: 2490444)
Index 197 = 57 38 76 (TrueColor: 3745356)
Index 198 = 19 0 38 (TrueColor: 1245222)
Index 199 = 28 19 38 (TrueColor: 1839910)
Index 200 = 191 0 255 (TrueColor: 12517631)
Index 201 = 223 127 255 (TrueColor: 14647295)
Index 202 = 124 0 165 (TrueColor: 8126629)
Index 203 = 145 82 165 (TrueColor: 9523877)
Index 204 = 95 0 127 (TrueColor: 6226047)
Index 205 = 111 63 127 (TrueColor: 7290751)
Index 206 = 57 0 76 (TrueColor: 3735628)
Index 207 = 66 38 76 (TrueColor: 4335180)
Index 208 = 28 0 38 (TrueColor: 1835046)
Index 209 = 33 19 38 (TrueColor: 2167590)
Index 210 = 255 0 255 (TrueColor: 16711935)
Index 211 = 255 127 255 (TrueColor: 16744447)
Index 212 = 165 0 165 (TrueColor: 10813605)
Index 213 = 165 82 165 (TrueColor: 10834597)
Index 214 = 127 0 127 (TrueColor: 8323199)
Index 215 = 127 63 127 (TrueColor: 8339327)
Index 216 = 76 0 76 (TrueColor: 4980812)
Index 217 = 76 38 76 (TrueColor: 4990540)
Index 218 = 38 0 38 (TrueColor: 2490406)
Index 219 = 38 19 38 (TrueColor: 2495270)
Index 220 = 255 0 191 (TrueColor: 16711871)
Index 221 = 255 127 223 (TrueColor: 16744415)
Index 222 = 165 0 124 (TrueColor: 10813564)
Index 223 = 165 82 145 (TrueColor: 10834577)
Index 224 = 127 0 95 (TrueColor: 8323167)
Index 225 = 127 63 111 (TrueColor: 8339311)
Index 226 = 76 0 57 (TrueColor: 4980793)
Index 227 = 76 38 66 (TrueColor: 4990530)
Index 228 = 38 0 28 (TrueColor: 2490396)
Index 229 = 38 19 33 (TrueColor: 2495265)
Index 230 = 255 0 127 (TrueColor: 16711807)
Index 231 = 255 127 191 (TrueColor: 16744383)
Index 232 = 165 0 82 (TrueColor: 10813522)
Index 233 = 165 82 124 (TrueColor: 10834556)
Index 234 = 127 0 63 (TrueColor: 8323135)
Index 235 = 127 63 95 (TrueColor: 8339295)
Index 236 = 76 0 38 (TrueColor: 4980774)
Index 237 = 76 38 57 (TrueColor: 4990521)
Index 238 = 38 0 19 (TrueColor: 2490387)
Index 239 = 38 19 28 (TrueColor: 2495260)
Index 240 = 255 0 63 (TrueColor: 16711743)
Index 241 = 255 127 159 (TrueColor: 16744351)
Index 242 = 165 0 41 (TrueColor: 10813481)
Index 243 = 165 82 103 (TrueColor: 10834535)
Index 244 = 127 0 31 (TrueColor: 8323103)
Index 245 = 127 63 79 (TrueColor: 8339279)
Index 246 = 76 0 19 (TrueColor: 4980755)
Index 247 = 76 38 47 (TrueColor: 4990511)
Index 248 = 38 0 9 (TrueColor: 2490377)
Index 249 = 38 19 23 (TrueColor: 2495255)
Index 250 = 0 0 0 (TrueColor: 0)
Index 251 = 51 51 51 (TrueColor: 3355443)
Index 252 = 102 102 102 (TrueColor: 6710886)
Index 253 = 153 153 153 (TrueColor: 10066329)
Index 254 = 204 204 204 (TrueColor: 13421772)
Index 255 = 255 255 255 (TrueColor: 16777215)