p; return mapping1;
}
//SchemaMapping
internal SchemaMapping(DbDataAdapter adapter, IDataReader dataReader, bool keyInfo)
{
this.adapter = adapter;
this.dataReader = dataReader;
if (keyInfo)//如果必须添加列和主键，就用dataReader的GetSchemaTable()返回一个DataTable
{
this.schemaTable = dataReader.GetSchemaTable();//返回一个 DataTable，它描述 SqlDataReader 的列元数据。可以查看msdn
}
}
//SetupSchema 创建
internal void SetupSchema(SchemaType schemaType, string sourceTableName, bool gettingData, DataColumn parentChapterColumn, object parentChapterValue)
{
MissingMappingAction action1;
MissingSchemaAction action2;
if (SchemaType.Mapped == schemaType)
{
action1 = this.adapter.MissingMappingAction;//确定传入数据没有匹配的表或列时需要执行的操作
action2 = this.adapter.MissingSchemaAction;//确定现有 DataSet 架构与传入数据不匹配时需要执行的操作。
if (!ADP.IsEmpty(sourceTableName))
{
this.tableMapping = this.adapter.GetTableMappingBySchemaAction(sourceTableName, sourceTableName, action1);//创建源表和 DataTable 之间的主映射。
goto Label_016D;
}
if (this.dataTable == null)
{
goto Label_016D;
}
int num1 = this.adapter.IndexOfDataSetTable(this.dataTable.TableName);
if (-1 != num1)
{
this.tableMapping = this.adapter.TableMappings[num1];
goto Label_016D;
}
switch (action1)
{
case MissingMappingAction.Passthrough://创建源列或源表，并使用其原始名称将其添加到 DataSet。
{
this.tableMapping = new DataTableMapping(this.dataTable.TableName, this.dataTable.TableName);
goto Label_016D;
}
case MissingMappingAction.Ignore://忽略没有映射的列或表。
{
this.tableMapping = null;
goto Label_016D;
}
case MissingMappingAction.Error://缺少指定的列映射，则生成 InvalidOperationException
{
throw ADP.MissingTableMappingDestination(this.dataTable.TableName);
}
}
throw ADP.InvalidMappingAction((int) action1);
}
if (SchemaType.Source != schemaType)
{
throw ADP.InvalidSchemaType((int) schemaType);
}
action1 = MissingMappingAction.Passthrough;
action2 = MissingSchemaAction.Add;
if (!ADP.IsEmpty(sourceTableName))
{
this.tableMapping = DataTableMappingCollection.GetTableMappingBySchemaAction(null, sourceTableName, sourceTableName, action1);
}
else if (this.dataTable != null)
{
int num2 = this.adapter.IndexOfDataSetTable(this.dataTable.TableName);
if (-1 != num2)
{
this.tableMapping = this.adapter.TableMappings[num2];
}
else
{
this.tableMapping = new DataTableMapping(this.dataTable.TableName, this.dataTable.TableName);////创建源表和 DataTable 之间的主映射。
}
}
Label_016D:
if (this.tableMapping != null)
{
if (this.dataTable == null)
{
this.dataTable = this.tableMapping.GetDataTableBySchemaAction(this.dataSet, action2);使用action2的 值获取DataSet的当前 DataTable。可以查看msdn
if (this.dataTable == null)
&
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