本文主要是介绍DBF文件初步了解（二）——DBF数据导出代码实现，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
上篇博客中主要记录一些关于DBF数据文件的概念性知识。包括DBF的数据结构和用处。在这里记录一下在C#中导出DBF文件的实现方式。DBF文件也是一种数据库文件，我们导出DBF文件也就是将数据库中的数据导出到DBF文件中。所以最主要的就是讲DataTable转换成DBF，包括数据和数据类型。
<span style="font-size:24px;">private bool WriteDBFfile(string filepath, DataTable dt, List<string> columnNames, string tableName, Dictionary<string, char> nametype = null){#region ***************************************写t**************************************nametype = ConvertColumnType(dt, tableName); ;FileStream fs = null;BinaryWriter bw = null;try{int rowCount = dt.Rows.Count;int columnCount = dt.Columns.Count;//if (rowCount > 0 && columnCount > 0)//{fs = new FileStream(filepath, FileMode.Create, FileAccess.Write);bw = new BinaryWriter(fs);byte tempByte;byte[] tempBytes;int tempInt;int[] fieldLength = new int[columnCount];int tempMax = 0;for (int i = 0; i < columnCount; i++){tempMax = 0;for (int j = 0; j < rowCount; j++){if (dt.Rows[j][i].ToString() != null && dt.Rows[j][i].ToString() != ""){if (dt.Rows[j][i].ToString().Length > tempMax){tempMax = dt.Rows[j][i].ToString().Length;}}}char dbfType = 'C';if (nametype.ContainsKey(columnNames[i].ToLower())){dbfType = nametype[columnNames[i].ToLower()];}if (tableName.StartsWith("F") && dbfType == 'N'){tempMax = 8;}else if (dbfType == 'N'){tempMax = 1;}//数êy字×?类àà型Dí长3¤度è至á少éù13，￡?此′?处′|直±接ó设éè置?所ù有óD列áD最×?小D?长3¤度è为a13fieldLength[i] = tempMax * 2 < 13 ? 13 : tempMax * 2;}/tempByte = 0x03;bw.Write(tempByte);tempBytes = new byte[3];tempInt = DateTime.Now.Year - 1900;tempBytes[0] = System.Convert.ToByte(tempInt);tempBytes[1] = System.Convert.ToByte(DateTime.Now.Month);tempBytes[2] = (byte)(DateTime.Now.Day);bw.Write(tempBytes);bw.Write(rowCount);tempInt = 33 + columnCount * 32;bw.Write((Int16)tempInt);tempInt = 1;for (int i = 0; i < columnCount; i++){tempInt += fieldLength[i];}bw.Write((Int16)tempInt);tempBytes = new byte[20];bw.Write(tempBytes);string tempColumnName;for (int i = 0; i < columnCount; i++){tempColumnName = columnNames[i];tempBytes = ConvertStringToBytes(tempColumnName, 11);bw.Write(tempBytes);char dbfType = 'C';if (nametype.ContainsKey(tempColumnName.ToLower())){dbfType = nametype[tempColumnName.ToLower()];}tempByte = (byte)dbfType;//数êy据Y类àà型Dí为a字×?符·?串′?bw.Write(tempByte);//第μú12-15为a保±￡留á?字×?节útempBytes = new byte[4];bw.Write(tempBytes);//第μú16个?字×?节ú为a字×?段?长3¤度ètempMax = fieldLength[i];tempByte = (byte)tempMax;bw.Write(tempByte);//接ó着×?第μú17-31都?为a保±￡留á?字×?节útempBytes = new byte[15];if (tableName.StartsWith("F") && dbfType == 'N' && tempColumnName.StartsWith("z")){tempBytes[0] = (byte)2;/}bw.Write(tempBytes);}tempByte = 0x0D;bw.Write(tempByte);object tempValue;for (int i = 0; i < rowCount; i++){//每?一ò?行DD第μú一ò?个?字×?节ú默?认è?为a20tempByte = 0x20;bw.Write(tempByte);for (int j = 0; j < columnCount; j++){tempValue = dt.Rows[i][j];if (tempValue != null){double val;if (double.TryParse(tempValue.ToString(), out val) && Equals(val, DbfsjdcViewModel_2015.FXB_DEF)){tempValue = "";}tempBytes = ConvertStringToBytes(tempValue.ToString(), fieldLength[j], true);bw.Write(tempBytes);}else{tempBytes = ConvertStringToBytes("", fieldLength[j], true);bw.Write(tempBytes);}}}}catch (Exception except){MessageBox.Show(except.Message);}finally{if (bw != null){bw.Close();bw.Dispose();}if (fs != null){fs.Close();fs.Dispose();}nametype.Clear();}return System.IO.File.Exists(filepath);#endregion ***************************************写D′入è?DBF文?件t**************************************}类型转换将String类型转换为Bytes类型方法：private byte[] ConvertStringToBytes(string tempStr, int limitLength, bool needAppendWhiteSpace = false){try{//originaldqdm,sourcelsgxmc,sourcelsgxdm,//org_dqdm,src_lsgxmc,src_lsgxdmswitch (tempStr){case "originaldqdm":tempStr = "org_dqdm";break;case "sourcelsgxmc":tempStr = "src_lsgxmc";break;case "sourcelsgxdm":tempStr = "src_lsgxdm";break;}byte[] tempBytes = UTF8Encoding.GetEncoding("gb2312").GetBytes(tempStr);byte[] result = null;if (tempBytes.Length == limitLength){result = tempBytes;}else if (tempBytes.Length > limitLength){result = new byte[limitLength];for (int i = 0; i < limitLength; i++){result[i] = tempBytes[i];}}else if (tempBytes.Length < limitLength){result = new byte[limitLength];for (int i = 0; i < tempBytes.Length; i++){result[i] = tempBytes[i];}if (needAppendWhiteSpace){for (int i = tempBytes.Length; i < limitLength; i++){result[i] = (byte)32;}}}return result;}catch (Exception except){MessageBox.Show(except.Message);return null;}}提取DataTable 列名，并转化为 Listprivate Dictionary<string, char> ConvertColumnType(DataTable dt, string tableName){Dictionary<string, char> lstType = new Dictionary<string, char>();foreach (DataColumn dc in dt.Columns){string colName = dc.ColumnName; string colType = dc.DataType.ToString(); char dbfType = 'C';switch (colType){case "System.Int32":case "System.Int64":case "System.Double":case "System.Decimal":case "System.UInt16":case "System.UInt32":case "System.UInt64":case "System.Byte":case "System.SByte":dbfType = 'N';break;case "System.DateTime":dbfType = 'D';break;case "System.Int16":case "System.String":dbfType = 'C';break;default:dbfType = 'C';break;}if (!lstType.ContainsKey(colName.ToLower())){lstType.Add(colName.ToLower(), dbfType);}}return lstType;}</span>这篇关于DBF文件初步了解（二）——DBF数据导出代码实现的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
