DBF文件读取与写入程序设计
下面介绍使用程序来读取和写入DBF文件：
首先新建一个窗体项目，各主要控件如下图所示：
读取DBF文件
读取DBF文件的内容并写到一个DataGridView控件中，采用如下函数：
/// <summary>
/// 读取DBF文件
/// </summary>
/// <param name="filepath">DBF文件路径</param>
/// <param name="dataGridView">DataGridView控件</param>
private void ReadDBFFile(string filepath, DataGridView dataGridView)
{
try
{
dataGridView.Rows.Clear();
dataGridView.Columns.Clear();
//打开文件
FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);
//跳过前面4个
br.ReadBytes(4);
//文件中的记录条数,即行数
int rowCount = br.ReadInt32();//4
//文件头的长度
int headLength = br.ReadInt16();//2
//每行的长度
int rowLength = br.ReadInt16();//2
//计算字段数目
int columnCount = (headLength - 33) / 32;
//跳过32-4-4-2-2=20个，直接到32
br.ReadBytes(20);
int i, j;
byte[] tempBytes = null;
byte tempByte;
int[] fieldLength = null;
//添加表格的列
if (columnCount > 0)
{
string tempColumnName;
fieldLength = new int[columnCount];
for (i = 0; i < columnCount; i++)
{
//读取前11个，为列名称
tempBytes = br.ReadBytes(11);
tempColumnName = ConvertBytesToString(tempBytes);
dataGridView.Columns.Add(tempColumnName, tempColumnName);
//跳过5个
br.ReadBytes(5);
//获取字段长度
tempByte = br.ReadByte();
fieldLength[i] = (int)tempByte;
//跳过剩下的字节，有32-11-5-1=15个
br.ReadBytes(15);
}
}
//获取文件头的最后一个字节，值应该为0D
tempByte = br.ReadByte();
if (tempByte == 0x0D)
{
//添加表格的行及数据
if (rowCount > 0)
{
string tempStr;
for (i = 0; i < rowCount; i++)
{
dataGridView.Rows.Add();
//每行数据中第一个20，跳过
br.ReadByte();
for (j = 0; j < columnCount; j++)
{
tempBytes = br.ReadBytes(fieldLength[j]);
tempStr = ConvertBytesToString(tempBytes);
dataGridView[j, i].Value = tempStr;
}
}
}
}
else
{
MessageBox.Show("文件头定义出现错误！",
"提示！", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
br.Close();
fs.Close();
}
catch (Exception except)
{
MessageBox.Show(except.Message,
"提示！", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
}
/// <summary>
/// 将字节组转换成为字符串
/// </summary>
/// <param name="tempBytes">字节数组</param>
/// <returns>DataGridView控件</returns>
public static string ConvertBytesToString(byte[] tempBytes)
{
string result = System.Text.Encoding.GetEncoding("gb2312").GetString(tempBytes);
return result;
}
/// <summary>
/// 将字节组转换成为整型
/// </summary>
/// <param name="tempBytes">字节数组</param>
/// <returns></returns>
public static Int32 ConvertBytesToInt32(byte[] tempBytes)
{
Int32 result = System.BitConverter.ToInt32(tempBytes, 0);
return result;
}
所以，在按钮“读取DBF文件button1”的单击事件添加调用上面读取DBF文件的代码：
private void 读取DBF文件button1_Click(object sender, EventArgs e)
{
if (File.Exists(filepathtextBox1.Text))
{
ReadDBFFile(filepathtextBox1.Text, dataGridView1);
}
}
写入DBF文件
同样，编写用于存储DBF文件的函数，如下：
/// <summary>
/// 保存DBF文件
/// </summary>
/// <param name="filepath">DBF文件保存路径</param>
/// <param name="dataGridView">表格对象</param>
private void WriteDBFFile(string filepath, DataGridView dataGridView)
{
try
{
int rowCount = dataGridView.RowCount;
int columnCount = dataGridView.ColumnCount;
if (rowCount > 0 && columnCount > 0)
{
FileStream fs = new FileStream(filepath, FileMode.Create, FileAccess.Write);
BinaryWriter bw = new BinaryWriter(fs);
byte tempByte;
byte[] tempBytes;
int i, j, tempInt;
int[] fieldLength = new int[columnCount];
int tempMax = 0;
for (i = 0; i < columnCount; i++)
{
tempMax = 0;
for (j = 0; j < rowCount; j++)
{
if (dataGridView[i, j].Value != null
&& dataGridView[i, j].Value.ToString() != "")
{
if (dataGridView[i, j].Value.ToString().Length > tempMax)
{
tempMax = dataGridView[i, j].Value.ToString().Length;
}
}
}
fieldLength[i] = tempMax * 2;
}
//写入文件头
{
//第0个字节为数据库类型
tempByte = 0x03;
bw.Write(tempByte);
tempBytes = new byte[3];
//第1个字节为保存时的年份-1990
tempInt = DateTime.Now.Year - 1900;
tempBytes[0] = System.Convert.ToByte(tempInt);
//第2个字节为保存时的月份
tempBytes[1] = System.Convert.ToByte(DateTime.Now.Month);
//第3个字节为保存时的日
tempBytes[2] = (byte)(DateTime.Now.Day);
bw.Write(tempBytes);
//第4-7个字节为行数
bw.Write(rowCount);
//第8-9字节为文件头的长度
tempInt = 33 + columnCount * 32;
bw.Write((Int16)tempInt);
//第10-11为每行数据所占长度
tempInt = 1;
for (i = 0; i < columnCount; i++)
{
tempInt += fieldLength[i];
}
bw.Write((Int16)tempInt);
//第12-31为保留字段，默认为0
tempBytes = new byte[20];
bw.Write(tempBytes);
string tempColumnName;
//开始写字段
for (i = 0; i < columnCount; i++)
{
tempColumnName = dataGridView.Columns[i].Name;
tempBytes = ConvertStringToBytes(tempColumnName, 11);
bw.Write(tempBytes);
//第11个字节为数据类型
tempByte = (byte)('C');//数据类型为字符串
bw.Write(tempByte);
//第12-15为保留字节
tempBytes = new byte[4];
bw.Write(tempBytes);
//第16个字节为字段长度
tempByte = (byte)fieldLength[i];
bw.Write(tempByte);
//接着第17-31都为保留字节
tempBytes = new byte[15];
bw.Write(tempBytes);
}
//最后以0D结尾
tempByte = 0x0D;
bw.Write(tempByte);
}
object tempValue;
//写入单元格数据
for (i = 0; i < rowCount; i++)
{
//每一行第一个字节默认为20
tempByte = 0x20;
bw.Write(tempByte);
for (j = 0; j < columnCount; j++)
{
tempValue = dataGridView[j, i].Value;
if (tempValue != null)
{
tempBytes = ConvertStringToBytes(tempValue.ToString(), fieldLength[j]);
bw.Write(tempBytes);
}
else
{
tempBytes = ConvertStringToBytes("", fieldLength[j]);
bw.Write(tempBytes);
}
}
}
bw.Close();
fs.Close();
}
else
{
MessageBox.Show("表格中没有数据",
"提示！", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
}
catch (Exception except)
{
MessageBox.Show(except.Message,
"提示！", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
}
/// <summary>
/// 将字符串转换成为字节数组
/// </summary>
/// <param name="tempStr"></param>
/// <param name="limitLength"></param>
/// <returns></returns>
public static byte[] ConvertStringToBytes(string tempStr,int limitLength)
{
byte[] result = null;
byte[] tempBytes = UTF8Encoding.GetEncoding("gb2312").GetBytes(tempStr);
if (tempBytes.Length == limitLength)
{
result = tempBytes;
}
else if (tempBytes.Length > 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];
}
}
return result;
}
同样，在按钮“保存DBF文件button1”的Click事件中添加调用上面的函数：
private void 保存DBF文件button1_Click(object sender, EventArgs e)
{
SaveFileDialog saveDg = new SaveFileDialog();
saveDg.Title = "保存DBF文件";
saveDg.Filter = "DBF文件(*.dbf)|*.dbf|所有文件(*.*)|*.*";
if (saveDg.ShowDialog() == DialogResult.OK)
{
WriteDBFFile(saveDg.FileName, dataGridView1);
}
}