CopyFrom Method

Overview

The CopyFrom method copies values from a source IDataRow into a current IDataRow using an explicit list of column metadata. Only columns defined in the metadata list are considered.

This method is commonly used during dataset merge, refresh, or synchronization operations, where column-level control is required and not all columns are guaranteed to exist in both source and current rows.

If the source row does not contain a value for a column defined in the metadata list, that column is skipped. If the current row does not contain the column but the source row does, the column is added to the current row, enabling schema evolution.

Declaration

/// <summary>
/// Copies column values from the source data row into the current data row using list of column metadata.
/// If the source data row does not contain a field specified in the metadata list, the column is skipped.
/// If the current data row does not contain a field specified in the metadata list but the source row does,
/// the column is added to the current row, supporting schema evolution.
/// </summary>
/// <param name="currentDataRow">Current data row.</param>
/// <param name="sourceDataRow">Source data row.</param>
/// <param name="listOfColumnMetadata">List of column metadata defining which columns to copy. Usually it is the list of column metadata or the source data table</param>
public static void CopyFrom(this IDataRow? currentDataRow, IDataRow sourceDataRow, IList<IColumnMetadata> listOfColumnMetadata)

Namespace and Assembly

Namespace: PocoDataSet.Extensions
Assembly: PocoDataSet.Extensions.dll

Behavior

• Only columns listed in listOfColumnMetadata are considered.
• If the source row does not contain a value for a column, that column is skipped.
• If the current row does not contain a column but the source row does, the column is added.
• Existing values in the current row are overwritten when the source provides a value.
• No type conversion or validation is performed.
• The method does not modify row state directly.

Usage Example

Assume two data tables with partially overlapping schemas:

// 1. Create data set
IDataSet dataSet = DataSetFactory.CreateDataSet();

// Create EmploymentType data table without Description column
IDataTable employmentTypeDataTable = dataSet.AddNewTable("EmploymentType");
employmentTypeDataTable.AddColumn("Id", DataTypeNames.INT32);
employmentTypeDataTable.AddColumn("Code", DataTypeNames.STRING);

// Add current data row to it
IDataRow employmentTypeCurrentDataRow = employmentTypeDataTable.AddNewRow();

// 2. Create refreshed data set
IDataSet refreshedDataSet = DataSetFactory.CreateDataSet();

// Create EmploymentType data table with Description column and refreshed data
IDataTable employmentTypeRefreshedTable = refreshedDataSet.AddNewTable("EmploymentType");
employmentTypeRefreshedTable.AddColumn("Id", DataTypeNames.INT32);
employmentTypeRefreshedTable.AddColumn("Code", DataTypeNames.STRING);
employmentTypeRefreshedTable.AddColumn("Description", DataTypeNames.STRING);

IDataRow employmentTypeRefreshedDataRow = employmentTypeRefreshedTable.AddNewRow();
employmentTypeRefreshedDataRow["Id"] = 1;
employmentTypeRefreshedDataRow["Code"] = "ET01";
employmentTypeRefreshedDataRow["Description"] = "Part Time";

// Call CopyFrom method and observe that employmentTypeCurrentDataRow contains "Description" field with "Part Time" value
employmentTypeCurrentDataRow.CopyFrom(employmentTypeRefreshedDataRow, employmentTypeRefreshedTable.Columns);

Typical Use Cases

• Merging refreshed data into an existing dataset.
• Applying changes from one dataset to another.
• Synchronizing rows during schema evolution.
• Copying selected columns during refresh or replace operations.

 

Table of Content POCO DataSet DataRow Members

 

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Business Process Programming in .Net
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