what are predefined methods that cannot be overrided in c#

Question

List some predefined methods that cannot be overidded in c#.

Jaish Mathews · Answer

Any built-in methods which is not virtual can't override. Below is some part of the built-in class DataTable definition. // // Summary: // This method returns an System.Xml.Schema.XmlSchemaSet instance containing the // Web Services Description Language (WSDL) that describes the System.Data.DataTable // for Web Services. // // Parameters: // schemaSet: // An System.Xml.Schema.XmlSchemaSet instance. // // Returns: // The System.Xml.Schema.XmlSchemaSet instance. public static XmlSchemaComplexType GetDataTableSchema(XmlSchemaSet schemaSet); // // Summary: // Commits all the changes made to this table since the last time System.Data.DataTable.AcceptChanges // was called. public void AcceptChanges(); // // Summary: // Begins the initialization of a System.Data.DataTable that is used on a form or // used by another component. The initialization occurs at run time. public virtual void BeginInit(); // // Summary: // Turns off notifications, index maintenance, and constraints while loading data. public void BeginLoadData(); // // Summary: // Clears the System.Data.DataTable of all data. public void Clear(); // // Summary: // Clones the structure of the System.Data.DataTable, including all System.Data.DataTable // schemas and constraints. // // Returns: // A new System.Data.DataTable with the same schema as the current System.Data.DataTable. public virtual DataTable Clone(); // // Summary: // Computes the given expression on the current rows that pass the filter criteria. // // Parameters: // expression: // The expression to compute. // // filter: // The filter to limit the rows that evaluate in the expression. // // Returns: // An System.Object, set to the result of the computation. If the expression evaluates // to null, the return value will be System.DBNull.Value. public object Compute( string expression, string filter); // // Summary: // Copies both the structure and data for this System.Data.DataTable. // // Returns: // A new System.Data.DataTable with the same structure (table schemas and constraints) // and data as this System.Data.DataTable.If these classes have been derived, the // copy will also be of the same derived classes. System.Data.DataTable.Copy creates // a new System.Data.DataTable with the same structure and data as the original // System.Data.DataTable. To copy the structure to a new System.Data.DataTable, // but not the data, use System.Data.DataTable.Clone. public DataTable Copy(); // // Summary: // Returns a System.Data.DataTableReader corresponding to the data within this System.Data.DataTable. // // Returns: // A System.Data.DataTableReader containing one result set, corresponding to the // source System.Data.DataTable instance. public DataTableReader CreateDataReader(); // // Summary: // Ends the initialization of a System.Data.DataTable that is used on a form or // used by another component. The initialization occurs at run time. public virtual void EndInit(); // // Summary: // Turns on notifications, index maintenance, and constraints after loading data. public void EndLoadData(); // // Summary: // Gets a copy of the System.Data.DataTable containing all changes made to it since // it was last loaded, or since System.Data.DataTable.AcceptChanges was called, // filtered by System.Data.DataRowState. // // Parameters: // rowStates: // One of the System.Data.DataRowState values. // // Returns: // A filtered copy of the System.Data.DataTable that can have actions performed // on it, and later be merged back in the System.Data.DataTable using System.Data.DataSet.Merge(System.Data.DataSet). // If no rows of the desired System.Data.DataRowState are found, the method returns // null. public DataTable GetChanges(DataRowState rowStates); // // Summary: // Gets a copy of the System.Data.DataTable that contains all changes made to it // since it was loaded or System.Data.DataTable.AcceptChanges was last called. // // Returns: // A copy of the changes from this System.Data.DataTable, or null if no changes // are found. public DataTable GetChanges(); // // Summary: // Gets an array of System.Data.DataRow objects that contain errors. // // Returns: // An array of System.Data.DataRow objects that have errors. public DataRow[] GetErrors(); // // Summary: // Populates a serialization information object with the data needed to serialize // the System.Data.DataTable. // // Parameters: // info: // A System.Runtime.Serialization.SerializationInfo object that holds the serialized // data associated with the System.Data.DataTable. // // context: // A System.Runtime.Serialization.StreamingContext object that contains the source // and destination of the serialized stream associated with the System.Data.DataTable. // // Exceptions: // T:System.ArgumentNullException: // The info parameter is a null reference (Nothing in Visual Basic). public virtual void GetObjectData(SerializationInfo info, StreamingContext context); You can see some methods are defined as virtual and can be overriden like below. e.g. clone(). public class Car : DataTable { public override DataTable Clone() { //your logic return base .Clone(); } } Methods defined as non virtuals can't override. The list is huge, but in VisualStudio, you can check is it virtual or not.

Nanddeep Nachan · Answer

Specifying methods as virtual, abstract, or override make them overriden Absense of these means a method is final.