DoRefreshMergeIfNoChangesExist Method

Overview

The DoRefreshMergeIfNoChangesExist method refreshes the current data set from a server snapshot only when the current data set contains no pending local changes.

If any row in any merged table is not Unchanged, the merge throws an InvalidOperationException to protect local work.

Declaration

/// <summary>
/// Dose RefreshIfNoChangesExist merge
/// </summary>
/// <param name="currentDataSet">Current data set</param>
/// <param name="refreshedDataSet">Refreshed data set</param>
/// <param name="mergeOptions">Merge options</param>
public static void DoRefreshMergeIfNoChangesExist(this IDataSet? currentDataSet, IDataSet refreshedDataSet, IMergeOptions mergeOptions)

Namespace and Assembly

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

Behavior

• If currentDataSet is null, the method returns without doing anything.
• For each table, if any row in current is Added, Modified, or Deleted, the merge throws.
• For clean tables, merges refreshed data by primary key when available; otherwise performs a non-keyed refresh strategy.
• Adds any tables that exist in the refreshed data set but not in the current data set.

Usage Example

// CURRENT: clean client-side snapshot.
IDataSet current = DataSetFactory.CreateDataSet();

IDataTable department = current.AddNewTable("Department");
department.AddColumn("Id", DataTypeNames.INT32, isNullable: false, isPrimaryKey: true);
department.AddColumn("Name", DataTypeNames.STRING);

IDataRow d1 = department.AddNewRow();
d1["Id"] = 1;
d1["Name"] = "Old Name";
current.AcceptChanges(); // IMPORTANT: make the dataset clean (rows become Unchanged)

// REFRESHED: server snapshot (Id=1 has updated Name).
IDataSet refreshed = DataSetFactory.CreateDataSet();

IDataTable rDepartment = refreshed.AddNewTable("Department");
rDepartment.AddColumn("Id", DataTypeNames.INT32, isNullable: false, isPrimaryKey: true);
rDepartment.AddColumn("Name", DataTypeNames.STRING);

IDataRow r1 = rDepartment.AddNewRow();
r1["Id"] = 1;
r1["Name"] = "New Name From Server";
refreshed.AcceptChanges();

IMergeOptions options = new MergeOptions();

// Act: refresh merge (allowed because CURRENT has no pending changes).
current.DoRefreshMergeIfNoChangesExist(refreshed, options);

// Assert: row refreshed
string name = department.Rows[0].GetDataFieldValue<string>("Name"); // "New Name From Server"

// If CURRENT had pending changes, DoRefreshMergeIfNoChangesExist would throw.

Notes

• Use this mode when you want a strict 'refresh only if clean' guarantee (for example, when a user clicks 'Reload' and you must not lose edits).
• If you want to refresh while keeping local edits, use DoRefreshMergePreservingLocalChanges instead.

 

Table of Content POCO DataSet DataSet Members

 

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Business Process Programming in .Net
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