Table into DataSet and Control DataTable（转）

private void DemonstrateMergeMissingSchema()
{
// Create a DataSet with one table, two columns,
// and three rows.
DataSet dataSet = new DataSet("dataSet");
DataTable table = new DataTable("Items");
DataColumn idColumn = new DataColumn("id",
Type.GetType("System.Int32"));
idColumn.AutoIncrement=true;
DataColumn itemColumn = new DataColumn("Item",
Type.GetType("System.Int32"));
// DataColumn array to set primary key.

DataColumn[] keyColumn= new DataColumn[1];
DataRow row;
// Create variable for temporary DataSet.
DataSet changeDataSet;

// Add RowChanged event handler for the table.
table.RowChanged+= new DataRowChangeEventHandler(
Row_Changed);
dataSet.Tables.Add(table);
table.Columns.Add(idColumn);
table.Columns.Add(itemColumn);

// Set primary key column.
keyColumn[0]= idColumn;
table.PrimaryKey=keyColumn;

// Add ten rows.
for(int i = 0; i <10;i++)
{
row=table.NewRow();
row["Item"]= i;
table.Rows.Add(row);
}

// Accept changes.
dataSet.AcceptChanges();
DataGrid2.DataSource=dataSet;
DataGrid2.DataBind();
//PrintValues(dataSet, "Original values");

// Change row values.
table.Rows[0]["Item"]= 50;
table.Rows[1]["Item"]= 111;

// Add one row.
row=table.NewRow();
row["Item"]=74;
table.Rows.Add(row);

// Insert code for error checking. Set one row in error.
table.Rows[1].RowError= "over 100";
//PrintValues(dataSet, "Modified and New Values");
// If the table has changes or errors, create a subset DataSet.
if(dataSet.HasChanges(DataRowState.Modified |
DataRowState.Added)& dataSet.HasErrors)
{
// Use GetChanges to extract subset.
changeDataSet = dataSet.GetChanges(
DataRowState.Modified|DataRowState.Added);
//PrintValues(changeDataSet, "Subset values");

// Insert code to reconcile errors. Reject the changes.
foreach(DataTable changeTable in changeDataSet.Tables)
{
if (changeTable.HasErrors)
{
foreach(DataRow changeRow in changeTable.Rows)
{
//Console.WriteLine(changeRow["Item"]);
if((int)changeRow["Item",
DataRowVersion.Current ]> 100)
{
changeRow.RejectChanges();
changeRow.ClearErrors();
}
}
}
}
// Add a column to the changeDataSet to change the schema.
changeDataSet.Tables["Items"].Columns.Add(
new DataColumn("newColumn"));
//PrintValues(changeDataSet, "Reconciled subset values");

// Add values to the rows for each column.
foreach(DataRow rowItem in changeDataSet.Tables["Items"].Rows)
{
rowItem["newColumn"] = "my new schema value";
}
DataGrid2.DataSource=dataSet;
DataGrid2.DataBind();
DataGrid3.DataSource=changeDataSet;
DataGrid3.DataBind();
// Merge changes back to first DataSet.
dataSet.Merge(changeDataSet, false,
System.Data.MissingSchemaAction.Add);
}
//PrintValues(dataSet, "Merged Values");
DataGrid1.DataSource=dataSet;
DataGrid1.DataBind();
}

private void Row_Changed(object sender, DataRowChangeEventArgs e)
{
Console.WriteLine("Row Changed " + e.Action.ToString()
+ "/table" + e.Row.ItemArray[0]);
}

private void PrintValues(DataSet dataSet, string label)
{
Console.WriteLine("/n" + label);
foreach(DataTable table in dataSet.Tables)
{
Console.WriteLine("TableName: " + table.TableName);
foreach(DataRow row in table.Rows)
{
foreach(DataColumn column in table.Columns)
{
Console.Write("/table " + row[column] );
}
Console.WriteLine();
}
}
}

id         Item
0         50
1         111
2         2
3         3
4         4
5         5
6         6
7         7
8         8
9         9
10        74

id         Item         newColumn
0         50             my new schema value
1         1               my new schema value
10         74             my new schema value

id         Item         newColumn
0           50            my new schema value
1            1             my new schema value
2             2
3             3
4             4
5             5
6             6
7             7
8             8
9             9
10         74         my new schema value