Replace / Reload Result Sets – Quick Start

For new searches or when you intentionally want to discard local edits, use Reload / Replace. This workflow clears the current rows and replaces them with refreshed rows, ending in a clean baseline where everything is Unchanged.

When to use Reload / Replace

• You ran a new search and want to show a new result set.
• You want to “start over” and discard in-progress edits.
• You are loading a new branch of data (for example, reloading children from scratch).
• You do not need to preserve local changes from the previous dataset snapshot.

What Reload / Replace does

• Clears current rows (discarding unsaved local edits).
• Copies all refreshed rows into the current dataset.
• Calls AcceptChanges() so the result becomes a clean baseline.

Core workflow

1. Keep a UI-bound observabl edataset in memory.
2. Request a refreshed dataset snapshot from the server.
3. Replace the current content with the refreshed snapshot (Reload / Replace) by using IObservableDataSet.DoReplaceMerge method.
4. The UI now reflects the new baseline; all rows are Unchanged.

Minimal working example

Assuming observable data set is used for UI binding, for example:

// 1. Create observable dataset
IObservableDataSet boundObservableDataSet = new ObservableDataSet();

// 2. Add Department table to the observable dataset
IObservableDataTable departmentObservableDataTable = boundObservableDataSet.AddNewTable("Department");
departmentObservableDataTable.AddColumn("Id", DataTypeNames.INT32);
departmentObservableDataTable.AddColumn("Name", DataTypeNames.STRING);

// 3. Add a row to the Department table (data row state is Added)
IObservableDataRow departmentObservableDataRow = departmentObservableDataTable.AddNewRow();
departmentObservableDataRow["Id"] = 1;
departmentObservableDataRow["Name"] = "Sales";

// 4. Add another row to the Department table, the values of which user hadn't cahnged (data row state is Unchanged)
IObservableDataRow departmentObservableDataRow = departmentObservableDataTable.AddNewRow();
departmentObservableDataRow["Id"] = 2;
departmentObservableDataRow["Name"] = "Emergency";
departmentObservableDataRow.AcceptChanges();
// The following line is a pseudo-code example of how UI can be bound to the observable data set.
// The actual binding code depends on the UI framework and is not part of POCO DataSet.
somePage.DataContext = boundObservableDataSet;

Assuming user clicked on Refresh button asking to refresh bound data. The following code imitates the server response.

// 1. Create refreshed dataset
IDataSet refreshedDataSet = DataSetFactory.CreateDataSet();

// 2. Add Department table to the refreshed dataset
IDataTable departmentRefreshedDataTable = refreshedDataSet.AddNewTable("Department");
departmentRefreshedDataTable.AddColumn("Id", DataTypeNames.INT32);
departmentRefreshedDataTable.AddColumn("Name", DataTypeNames.STRING);

// 3. Add two rows to the Department table which imitate changed data in the database
IDataRow departmentRefreshedDataRow = departmentRefreshedDataTable.AddNewRow();
departmentRefreshedDataRow["Id"] = 1;
departmentRefreshedDataRow["Name"] = "Sales and Marketing";

departmentRefreshedDataRow = departmentRefreshedDataTable.AddNewRow();
departmentRefreshedDataRow["Id"] = 2;
departmentRefreshedDataRow["Name"] = "Emergency Department";

// 4. Mark all rows as Unchanged to indicate they are clean server values
refreshedDataSet.AcceptChanges();

Call IObservableDataSet.DoReplaceMerge method to discard all local changes and replace all local data by refreshed snapshot:

IObservableMergeOptions observableMergeOptions = new ObservableMergeOptions();
boundObservableDataSet.DoReplaceMerge(refreshedDataSet, observableMergeOptions);

// Observe that the name of the Sales department is updated to "Sales and Marketing"
string nameOfSalesDepartment = (string)currentDepartment.Rows[0]["Name"];

// Observe that the name of the Emergency department is updated to "Emergency Department"
string nameOfEmergencyDepartment = (string)currentDepartment.Rows[1]["Name"];

 

Table of Content POCO DataSet Quick Start

 

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Business Process Programming in .Net
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