If the DataRow.Delete() method is called, the RowState property of the corresponding row will be set to DataRowState.Deleted. When the status of a row is DataRowState.Deleted, we cannot access this row under normal circumstances. If you need to retrieve deleted original data, you can use the overloaded method of its entry property to pass the DataRowVersion.Original parameter.
The code is like this:
if (typedDataRow.RowState == DataRowState.Deleted) id = (string)typedDataRow["CustomerID", DataRowVersion.Original];
Use datatable.Rows[i].Delete() to delete rows or press the Del key on the DataGrid to delete rows and then access the table again. "Cannot pass deleted rows" appears. row to access the row's information" error. The reasons are as follows:
After Delete(), the datatable.AccepteChanges() method is required to confirm the complete deletion, because Delete() only marks the status of the corresponding column as deleted, and can also be rolled back through datatable.RejectChanges() to cancel the row. delete.
So If you want to completely delete the datarow, you need to use the Delete() and AccepteChanges() methods at the same time , or use the datatable.Rows.RemoveAt(i) method to directly delete , where i Represents the row index, and another one is datatable.Rows.Remove(DataRow dr) to delete the specified row.
However, when using datatable.Rows.RemoveAt(i), please note that if you use datatable.Rows.RemoveAt(0); datatable.Rows.RemoveAt(1); continuously, you will not delete 0, 1 in the original table. rows, but after deleting 0 rows, the original 1 row becomes 0 rows, so datatable.Rows.RemoveAt(1) actually deletes 2 rows of the original table. At this time it should be i = i - 1;
So you should use datatable.Rows.RemoveAt(i) with caution
Small note:
Row version (DataRowVersion )
The row (DataRow) object has four different row versions, namely Current, Original, proposed and default. A brief description of these row versions follows.
Current: Indicates the current value of the row. No version of the row exists for a row in the deleted state.
Original: Represents the original value of the row. The row version in the Added state does not exist
Proposed: Indicates the recommended value of the row. This row version exists for rows that do not belong to the table, that is, rows in the Detached state; this row version also exists for rows that are being edited.
Default: Indicates the default version of the row. The default row version for rows in the Added, Modified, or Unchanged state is current; for rows in the deleted state, the default row version is original. The default version for rows in the Detached state is proposed.
The above is the content of C# Table.Rows[index].Delete(). For more related content, please pay attention to the PHP Chinese website (www.php.cn)!

C# is not always tied to .NET. 1) C# can run in the Mono runtime environment and is suitable for Linux and macOS. 2) In the Unity game engine, C# is used for scripting and does not rely on the .NET framework. 3) C# can also be used for embedded system development, such as .NETMicroFramework.

C# plays a core role in the .NET ecosystem and is the preferred language for developers. 1) C# provides efficient and easy-to-use programming methods, combining the advantages of C, C and Java. 2) Execute through .NET runtime (CLR) to ensure efficient cross-platform operation. 3) C# supports basic to advanced usage, such as LINQ and asynchronous programming. 4) Optimization and best practices include using StringBuilder and asynchronous programming to improve performance and maintainability.

C# is a programming language released by Microsoft in 2000, aiming to combine the power of C and the simplicity of Java. 1.C# is a type-safe, object-oriented programming language that supports encapsulation, inheritance and polymorphism. 2. The compilation process of C# converts the code into an intermediate language (IL), and then compiles it into machine code execution in the .NET runtime environment (CLR). 3. The basic usage of C# includes variable declarations, control flows and function definitions, while advanced usages cover asynchronous programming, LINQ and delegates, etc. 4. Common errors include type mismatch and null reference exceptions, which can be debugged through debugger, exception handling and logging. 5. Performance optimization suggestions include the use of LINQ, asynchronous programming, and improving code readability.

C# is a programming language, while .NET is a software framework. 1.C# is developed by Microsoft and is suitable for multi-platform development. 2..NET provides class libraries and runtime environments, and supports multilingual. The two work together to build modern applications.

C#.NET is a powerful development platform that combines the advantages of the C# language and .NET framework. 1) It is widely used in enterprise applications, web development, game development and mobile application development. 2) C# code is compiled into an intermediate language and is executed by the .NET runtime environment, supporting garbage collection, type safety and LINQ queries. 3) Examples of usage include basic console output and advanced LINQ queries. 4) Common errors such as empty references and type conversion errors can be solved through debuggers and logging. 5) Performance optimization suggestions include asynchronous programming and optimization of LINQ queries. 6) Despite the competition, C#.NET maintains its important position through continuous innovation.

The future trends of C#.NET are mainly focused on three aspects: cloud computing, microservices, AI and machine learning integration, and cross-platform development. 1) Cloud computing and microservices: C#.NET optimizes cloud environment performance through the Azure platform and supports the construction of an efficient microservice architecture. 2) Integration of AI and machine learning: With the help of the ML.NET library, C# developers can embed machine learning models in their applications to promote the development of intelligent applications. 3) Cross-platform development: Through .NETCore and .NET5, C# applications can run on Windows, Linux and macOS, expanding the deployment scope.

The latest developments and best practices in C#.NET development include: 1. Asynchronous programming improves application responsiveness, and simplifies non-blocking code using async and await keywords; 2. LINQ provides powerful query functions, efficiently manipulating data through delayed execution and expression trees; 3. Performance optimization suggestions include using asynchronous programming, optimizing LINQ queries, rationally managing memory, improving code readability and maintenance, and writing unit tests.

How to build applications using .NET? Building applications using .NET can be achieved through the following steps: 1) Understand the basics of .NET, including C# language and cross-platform development support; 2) Learn core concepts such as components and working principles of the .NET ecosystem; 3) Master basic and advanced usage, from simple console applications to complex WebAPIs and database operations; 4) Be familiar with common errors and debugging techniques, such as configuration and database connection issues; 5) Application performance optimization and best practices, such as asynchronous programming and caching.


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