[C#]
private void CreateRelation() {
// Get the DataColumn objects from two DataTable objects in a DataSet.
DataColumn parentCol;
DataColumn childCol;
// Code to get the DataSet not shown here.
parentCol = DataSet1.Tables["Customers"].Columns["CustID"];
childCol = DataSet1.Tables["Orders"].Columns["CustID"];
// Create DataRelation.
DataRelation relCustOrder;
relCustOrder = new DataRelation("CustomersOrders", parentCol, childCol);
// Add the relation to the DataSet.
DataSet1.Relations.Add(relCustOrder);
}
private void CreateRelation() {
// Get the DataColumn objects from two DataTable objects in a DataSet.
DataColumn parentCol;
DataColumn childCol;
// Code to get the DataSet not shown here.
parentCol = DataSet1.Tables["Customers"].Columns["CustID"];
childCol = DataSet1.Tables["Orders"].Columns["CustID"];
// Create DataRelation.
DataRelation relCustOrder;
relCustOrder = new DataRelation("CustomersOrders", parentCol, childCol);
// Add the relation to the DataSet.
DataSet1.Relations.Add(relCustOrder);
}
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Access本身没有定义关系,用代码可以修改Access本身吗?To: wangsaohui:gridZong.DataSource = ds;
gridZong.DataMember = "Zongzhang";//这两句应该怎麽写?
gridZhi.DataSource = 你新建的关系 ;(类似于例子中的relCustOrder)
我在我的代码中加了DataRelation的代码,错误提示:
未处理的“System.NullReferenceException”类型的异常出现在 ManageSystem.exe 中。其他信息: 未将对象引用设置到对象的实例。strConn = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" +
FormCreateDatabase.Path;//返回文件路径
string strSqlZong = "SELECT * FROM Zongzhang";
string strSqlZhi = "SELECT * FROM Zhichu";
OleDbDataAdapter daZong = new OleDbDataAdapter( strSqlZong, strConn );
OleDbDataAdapter daZhi = new OleDbDataAdapter( strSqlZhi, strConn );
daZong.MissingSchemaAction = MissingSchemaAction.AddWithKey;
daZhi.MissingSchemaAction = MissingSchemaAction.AddWithKey;
DataSet ds = new DataSet( );
ds.Clear( );DataColumn colZong = ds.Tables[ "Zongzhang" ].Columns[ "DateTime" ];//错误提示
//停在此行
DataColumn colZhi = ds.Tables[ "Zhichu" ].Columns[ "DateTime" ]; DataRelation rel = new DataRelation( "ZongZhi", colZong, colZhi );
ds.Relations.Add ( rel );
daZong.Fill( ds ); /*从此行不知对不对
daZhi.Fill( ds );gridZong.DataSource = ds;
gridZong.DataMember = "Zongzhang";gridZhi.DataSource = rel;
gridZhi.DataMember = "ZongZhi"; */请帮忙给看一看。多谢。
daZhi.Fill( ds );
放在
DataColumn colZong = ds.Tables[ "Zongzhang" ].Columns[ "DateTime" ];//错误提示
之前
daZhi.Fill( ds );
改为:daZong.Fill( ds, "Zongzhang" );
daZhi.Fill( ds, "Zhichu" );
daZhi.Fill( ds, "Zhichu" );
放到前面,放到
DataColumn colZong = ds.Tables[ "Zongzhang" ].Columns[ "DateTime1" ];
前面
datetime最好改名字,这是sqlserver的保留字。否则没有填充,DS中还没有datatable和相应的列,如何建立关系呢
FormCreateDatabase.Path;
string strSqlZong = "SELECT * FROM Zongzhang";
string strSqlZhi = "SELECT * FROM Zhichu";
OleDbDataAdapter daZong = new OleDbDataAdapter( strSqlZong, strConn );
OleDbDataAdapter daZhi = new OleDbDataAdapter( strSqlZhi, strConn );
daZong.MissingSchemaAction = MissingSchemaAction.AddWithKey;
daZhi.MissingSchemaAction = MissingSchemaAction.AddWithKey;
DataSet ds = new DataSet( );
ds.Clear( );
daZong.Fill( ds, "Zongzhang" );
daZhi.Fill( ds, "Zhichu" );DataRelation rel = new DataRelation( "ZongZhi",
ds.Tables[ "Zongzhang" ].Columns[ "DateTimeZong" ],
ds.Tables[ "Zhichu" ].Columns[ "DateTimeZhi" ] );
ds.Relations.Add( rel );gridZong.DataSource = ds; /*是不是DataSource
gridZong.DataMember = "Zongzhang"; 和DataMember的
设置问题*/
gridZhi.DataSource = ds;
gridZhi.DataMember = "Zhichu";