如何使用oledb使用其各自的.dbc文件从.dbf文件读取/写入数据？

Question

我被指示使用C++编写测试程序，能够从Visual Fox Pro数据库中读取数据。我只有被给予的文件，我无法从这些文件中读取数据。

我在网上发现了一些能够成功打开访问文件的代码，并且我能够更改它以便打开我的数据库文件。

我遇到的问题是我可以使用.dbc文件获取任何.dbf文件的列信息，但是当我尝试使用rs.movenext（）存储在行中的数据时，没有数据从数据库文件中显示。

该代码作为整体适用于访问文件，使用注释掉的连接字符串。出于某种原因，当我切换到.dbf和.dbc文件时，行数据无法显示。

任何见解都会很棒。我的代码如下。

int _tmain(int argc, _TCHAR* argv[]) 
{ 
CoInitialize(NULL); 

CDataSource ds; 
CSession ss; 
CCommand<CDynamicAccessor> rs; 
DBTYPE dbt; 
int i; 


if (ds.OpenFromInitializationString(_T("Provider=vfpoledb.1;Data Source=C:\\Users\\xx\\xx\\xx\\appdata.dbc;Collating Sequence=general;"))) { 
    //if (ds.OpenFromInitializationString(_T("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Testdata.mdb"))) { 
    printf("CDataSource Error\n"); 
    return 1; 
} 



if (ss.Open(ds)) { 
    printf("CSession Error\n"); 
    return 1; 
} 
if (rs.Open(ss, _T("Select * From AppReg01.dbf"))) { 
    printf("CCommand Error\n"); 
    return 1; 
} 
int count = 0; 
for (i = 1; i <= (int)rs.GetColumnCount(); i++) { 
    rs.GetColumnType(i, &dbt); 
    printf("Column number = %d, Column name = %S, Column type = %d\n", i, rs.GetColumnName(i), dbt); 


} 


while (!rs.MoveNext()) { 
    printf_s("blah: %S, %S \n \n", rs.GetValue(1), rs.GetValue(2)); \ 
    count++; 
} 
rs.Close(); 
ss.Close(); 
ds.Close(); 



CoUninitialize(); 
return 0; 
} 

我的输出：

Column number = 1, Column name = kname, Column type = 128 
Column number = 2, Column name = lname, Column type = 129 
Column number = 3, Column name = key, Column type = 128 
Column number = 4, Column name = rtype, Column type = 131 
Column number = 5, Column name = type, Column type = 131 
Column number = 6, Column name = access, Column type = 131 
Column number = 7, Column name = shortvalue, Column type = 128 
Column number = 8, Column name = value, Column type = 13 
Column number = 9, Column name = props, Column type = 13 
Column number = 10, Column name = comment, Column type = 13 
blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah:  
blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: 
blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: 
blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: 
blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: 
blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: blah: 
Press any key to continue . . . 

Answer 1

那会不会％s且不％S（不知道我真正的C是生锈）？这适用于我：

int _tmain(int argc, _TCHAR* argv[]) 
{ 
CoInitialize(NULL); 

CDataSource ds; 
CSession ss; 
CCommand<CDynamicAccessor> rs; 
DBTYPE dbt; 
int i; 


if (ds.OpenFromInitializationString(_T("Provider=vfpoledb;Data Source=C:\\Program Files (x86)\\Microsoft Visual FoxPro 9\\Samples\\Northwind\\northwind.dbc;"))) { 
// if (ds.OpenFromInitializationString(_T("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=d:\\data\\Northwind.mdb"))) { 
    printf("CDataSource Error\n"); 
    return 1; 
} 



if (ss.Open(ds)) { 
    printf("CSession Error\n"); 
    return 1; 
} 
if (rs.Open(ss, _T("Select * From Customers"))) { 
    printf("CCommand Error\n"); 
    return 1; 
} 
int count = 0; 
for (i = 1; i <= (int)rs.GetColumnCount(); i++) { 
    rs.GetColumnType(i, &dbt); 
    printf("Column number = %d, Column name = %S, Column type = %d\n", i, rs.GetColumnName(i), dbt); 


} 

while (!rs.MoveNext()) { 
    printf_s("blah: %s, %s \n \n", rs.GetValue(1), rs.GetValue(2)); 
    count++; 
} 
rs.Close(); 
ss.Close(); 
ds.Close(); 



CoUninitialize(); 
return 0; 
}