c#读取access数据库
代码如下:
OleDbDataAdapter da = new OleDbDataAdapter("Select * from Grade", objConnection);
DataSet ds = new DataSet();
DataTable myDataTable = ds.Tables["Grade"];
da.Fill(ds,"Grade");
foreach (DataRow myDataRow in myDataTable.Rows)
{
Console.WriteLine("Name = " + myDataRow["name"]);
Console.WriteLine("Sex = " + myDataRow["sex"]);
Console.WriteLine("Remark = " + myDataRow["remark"]);
Console.WriteLine("Grade = " + myDataRow["grade"]);
}
以上语句在执行到foreach的时候出了一个异常,说是Object reference not set to an instance of an object.出错的代码是myDtaTable.Rows.
烦请高人指点!
我觉得对你最好的办法就是单步调试,看看每个变量是否都有值,是否都是在引用的时候已经创建了。这个异常基本上就是你引用的对象没有创建出来。
for(int i=1;i <=myDataTable.Rows.Count;i++)
{
Console.WriteLine("Name = " + myDataTable.Rows["name"]);
Console.WriteLine("Sex = " + myDataTable.Rows["sex"]);
Console.WriteLine("Remark = " + myDataTable.Rows["remark"]);
Console.WriteLine("Grade = " + myDataTable.Rows["grade"]);
}
lz再试试看。
相关问答:
请各位指点下:程序代码如下mingchen = "C:\文件路径\"
cat = New ADOX.Catalog
cat.Create("Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=" & min ......
最近在做个网上商城,购物车模块,没有做过,麻烦各位帮忙说下大致说下思路,能发一份源码更好。小弟先谢过各位了;
QQ:413763818;
eamil:swebook@126.com
网上一大堆!
www.51aspx.com
去下 ......
麻烦各位帮忙看看啊
代码如下:
CoInitialize(NULL);
_ConnectionPtr pConn(__uuidof(Connection));
_RecordsetPtr pRst(__uuidof(Recordset));
pConn->ConnectionString="Provider ......
CREATE TABLE Product(model integer,
maker varchar(20),
CONSTRAINT SAND PRIMARY KEY (model),
CONSTRAINT PANDA FOREIGN KEY (model) REFERENCES PC (model)
ON DELETE CASCADE ......