diff --git a/maker/csharp/DbMaker/HeaderBlock.cs b/maker/csharp/DbMaker/HeaderBlock.cs
new file mode 100644
index 0000000..b561e0f
--- /dev/null
+++ b/maker/csharp/DbMaker/HeaderBlock.cs
@@ -0,0 +1,57 @@
+namespace DbMaker
+{
+    /// <summary>
+    ///     header block class
+    /// </summary>
+    public class HeaderBlock
+    {
+        public HeaderBlock(long indexStartIp, int indexPtr)
+        {
+            IndexStartIp = indexStartIp;
+            IndexPtr = indexPtr;
+        }
+
+        /// <summary>
+        ///     index block start ip address
+        /// </summary>
+        public long IndexStartIp { get; set; }
+
+        /// <summary>
+        ///     ip address
+        /// </summary>
+        public int IndexPtr { get; set; }
+
+        public HeaderBlock SetIndexStartIp(long indexStartIp)
+        {
+            IndexStartIp = indexStartIp;
+            return this;
+        }
+
+        public HeaderBlock SetIndexPtr(int indexPtr)
+        {
+            IndexPtr = indexPtr;
+            return this;
+        }
+
+        /// <summary>
+        ///     get the bytes for db storage
+        /// </summary>
+        /// <returns></returns>
+        public byte[] GetBytes()
+        {
+            /*
+             * +------------+-----------+
+             * | 4bytes        | 4bytes    |
+             * +------------+-----------+
+             *  start ip      index ptr
+            */
+
+            var b = new byte[8];
+
+            Util.writeIntLong(b, 0, IndexStartIp);
+            Util.writeIntLong(b, 4, IndexPtr);
+
+            return b;
+        }
+    }
+}
\ No newline at end of file
diff --git a/maker/csharp/DbMaker/IndexBlock.cs b/maker/csharp/DbMaker/IndexBlock.cs
new file mode 100644
index 0000000..b456126
--- /dev/null
+++ b/maker/csharp/DbMaker/IndexBlock.cs
@@ -0,0 +1,92 @@
+namespace DbMaker
+{
+    /// <summary>
+    ///     item index class
+    /// </summary>
+    public class IndexBlock
+    {
+        private static int LENGTH = 12;
+
+        public IndexBlock(long startIp, long endIp, int dataPtr, int dataLen)
+        {
+            StartIp = startIp;
+            EndIp = endIp;
+            DataPtr = dataPtr;
+            DataLen = dataLen;
+        }
+
+        /**
+         * start ip address
+         */
+        public long StartIp { get; set; }
+
+        /**
+         * end ip address
+         */
+        public long EndIp { get; set; }
+
+        /**
+         * data ptr and data length
+         */
+        public int DataPtr { get; set; }
+
+        /**
+         * data length
+         */
+        public int DataLen { get; set; }
+
+        public IndexBlock SetStartIp(long startIp)
+        {
+            StartIp = startIp;
+            return this;
+        }
+
+        public IndexBlock SetEndIp(long endIp)
+        {
+            EndIp = endIp;
+            return this;
+        }
+
+        public IndexBlock SetDataPtr(int dataPtr)
+        {
+            DataPtr = dataPtr;
+            return this;
+        }
+
+        public IndexBlock SetDataLen(int dataLen)
+        {
+            DataLen = dataLen;
+            return this;
+        }
+
+        public static int GetIndexBlockLength()
+        {
+            return LENGTH;
+        }
+
+        /**
+     * get the bytes for storage
+     * 
+     * @return    byte[]
+    */
+        public byte[] GetBytes()
+        {
+            /*
+             * +------------+-----------+-----------+
+             * | 4bytes        | 4bytes    | 4bytes    |
+             * +------------+-----------+-----------+
+             *  start ip      end ip      data ptr + len 
+            */
+            var b = new byte[12];
+
+            Util.writeIntLong(b, 0, StartIp); //start ip
+            Util.writeIntLong(b, 4, EndIp); //end ip
+
+            //write the data ptr and the length
+            var mix = DataPtr | DataLen << 24 & 0xFF000000L;
+            Util.writeIntLong(b, 8, mix);
+
+            return b;
+        }
+    }
+}
\ No newline at end of file
diff --git a/maker/csharp/DbMaker/Util.cs b/maker/csharp/DbMaker/Util.cs
new file mode 100644
index 0000000..60e493e
--- /dev/null
+++ b/maker/csharp/DbMaker/Util.cs
@@ -0,0 +1,143 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Text;
+
+namespace DbMaker
+{
+    /// <summary>
+    /// util class 
+    /// </summary>
+    public static class Util
+    {
+        /**
+     * write specfield bytes to a byte array start from offset
+     * 
+     * @param    b
+     * @param    offset
+     * @param    v
+     * @param    bytes
+    */
+        public static void write(byte[] b, int offset, long v, int bytes)
+        {
+            for (int i = 0; i < bytes; i++)
+            {
+                b[offset++] = (byte)((v >> (8 * i)) & 0xFF);
+            }
+        }
+
+        /**
+         * write a int to a byte array
+         * 
+         * @param    b
+         * @param    offet
+         * @param    v
+        */
+        public static void writeIntLong(byte[] b, int offset, long v)
+        {
+            b[offset++] = (byte)((v >> 0) & 0xFF);
+            b[offset++] = (byte)((v >> 8) & 0xFF);
+            b[offset++] = (byte)((v >> 16) & 0xFF);
+            b[offset] = (byte)((v >> 24) & 0xFF);
+        }
+
+        /**
+         * get a int from a byte array start from the specifiled offset
+         * 
+         * @param    b
+         * @param    offset
+        */
+        public static long getIntLong(byte[] b, int offset)
+        {
+            return (
+                ((b[offset++] & 0x000000FFL)) |
+                ((b[offset++] << 8) & 0x0000FF00L) |
+                ((b[offset++] << 16) & 0x00FF0000L) |
+                ((b[offset] << 24) & 0xFF000000L)
+            );
+        }
+
+        /**
+         * get a int from a byte array start from the specifield offset
+         * 
+         * @param    b
+         * @param    offset
+        */
+        public static int getInt3(byte[] b, int offset)
+        {
+            return (
+                (b[offset++] & 0x000000FF) |
+                (b[offset++] & 0x0000FF00) |
+                (b[offset] & 0x00FF0000)
+            );
+        }
+
+        public static int getInt2(byte[] b, int offset)
+        {
+            return (
+                (b[offset++] & 0x000000FF) |
+                (b[offset] & 0x0000FF00)
+            );
+        }
+
+        public static int getInt1(byte[] b, int offset)
+        {
+            return (
+                (b[offset] & 0x000000FF)
+            );
+        }
+
+        /**
+         * string ip to long ip
+         * 
+         * @param    ip
+         * @return    long
+        */
+        public static long ip2long(String ip)
+        {
+            IPAddress ipaddress = IPAddress.Parse(ip);
+            byte[] addbuffer = ipaddress.GetAddressBytes();
+            Array.Reverse(addbuffer);
+            return BitConverter.ToInt64(addbuffer, 0);
+        }
+
+        /**
+         * int to ip string 
+         * 
+         * @param    ip
+         * @return    string
+        */
+        public static String long2ip(long ip)
+        {
+            StringBuilder sb = new StringBuilder();
+
+            sb
+            .Append((ip >> 24) & 0xFF).Append('.')
+            .Append((ip >> 16) & 0xFF).Append('.')
+            .Append((ip >> 8) & 0xFF).Append('.')
+            .Append((ip >> 0) & 0xFF);
+
+            return sb.ToString();
+        }
+
+        /**
+         * check the validate of the specifeld ip address
+         * 
+         * @param    ip
+         * @return    boolean
+        */
+        public static Boolean isIpAddress(String ip)
+        {
+            String[] p = ip.Split("\\.");
+            if (p.Length != 4) return false;
+
+            foreach (var pp in p)
+            {
+                if (pp.Length > 3) return false;
+                int val = Convert.ToInt32(pp); //Integer.valueOf(pp);
+                if (val > 255) return false;
+            }
+            return true;
+        }
+    }
+}