What is ADO.NET?What are the key components of ADO.NET?What are the ADO.NET namespaces?What is the meaning of object pooling?What are the differences between ADO.NET and classic ADO?Explain the architecture of ADO.NET.?What is a Connection String in ADO.NET C#??How do you establish a database connection using ADO.NET?Explain the concept of Connection Pooling in ADO.NET C#.Differentiate between Object pooling and Connection pooling in C#?What is a DataReader in ADO.NET? Explain with C# example?What is the functionality of CommandBehavior.SchemaOnly?Why CommandBehavior.SingleResult flag is used in ADO.NET?What does CommandBehavior.SingleRow do in ADO.NET?How we can get multiple results by DataReader using same connection in C#?How can we force the connection object to close after my DataReader is closed?What is a DataSet in ADO.NET? Explain with C# example?What are typed and un-typed datasets in ADO.NET C#?Write down some of the characteristic of DataSet?What is the difference between dataSet and DataReader?Why is DataSet Slower than DataReader? Explain with Example.How does DataSet handle data in a disconnected environment?What is the Difference between connected and disconnected architectire?Explain HasChanges() method of DataSet in C#.Explain GetChanges() method with detaild C# Example.Explain RejectChanges() method with C# Example.Explain AcceptChanges() method with C# Example.What are the various methods provided by DataSet for XML in C#?What is the purpose of DataAdapter in ADO.NET?Explain the steps involved in retrieving data using DataAdapter.
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Understanding the RejectChanges() Method in ADO.NET with C#

In C#, the RejectChanges() method is an important feature of the DataTable class in ADO.NET. It is used to cancel any changes made to the rows within a DataTable and restore their original values from when it was first loaded or when the last call to AcceptChanges() was made. This method is particularly useful when you want to discard changes made to a DataTable without affecting the corresponding data in the database.

The primary purpose of RejectChanges() is to roll back changes made to a DataTable and its rows to their previous state, effectively canceling any pending modifications.

Illustration with Complete Source Code

Let's illustrate how to use the RejectChanges() method with a complete C# source code example:


using System;
using System.Data;

class Program
{
    static void Main()
    {
        // Create a DataTable with some sample data
        DataTable dataTable = new DataTable("Employee");
        dataTable.Columns.Add("EmployeeID", typeof(int));
        dataTable.Columns.Add("FirstName", typeof(string));
        dataTable.Columns.Add("LastName", typeof(string));

        // Add a new row to the DataTable
        DataRow newRow = dataTable.NewRow();
        newRow["EmployeeID"] = 1;
        newRow["FirstName"] = "John";
        newRow["LastName"] = "Doe";
        dataTable.Rows.Add(newRow);

        // Modify the data in the DataRow
        newRow["FirstName"] = "Jane";
        newRow["LastName"] = "Smith";

        Console.WriteLine("Original Data:");
        PrintDataTable(dataTable);

        // Reject the changes and restore the original values
        dataTable.RejectChanges();

        Console.WriteLine("\nAfter Rejecting Changes:");
        PrintDataTable(dataTable);
    }

    static void PrintDataTable(DataTable dt)
    {
        foreach (DataRow row in dt.Rows)
        {
            Console.WriteLine($"{row["EmployeeID"]}, {row["FirstName"]}, {row["LastName"]}");
        }
    }
}

In this example:

  • We create a DataTable named "Employee" with columns for EmployeeID, FirstName, and LastName.
  • A new DataRow (newRow) is added to the DataTable with initial values.
  • We then modify the FirstName and LastName values of the DataRow.
  • The original data is printed before and after rejecting changes using the RejectChanges() method.

Expected Output

After executing the code, the output will demonstrate how the RejectChanges() method restores the DataTable and its rows to their original state:


Original Data:
1, John, Doe

After Rejecting Changes:
1, John, Doe

As you can see, after calling RejectChanges() on the DataTable, the modifications made to the DataRow are undone, and the data is reverted to its original values. This is a useful feature when working with DataTables that you want to temporarily modify but may need to discard those changes later.

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