Changing Layer DataSource using ArcObjects?

Question

I want to change data source information of a layer. Lets say I have a MXD file in dev env configured with dev environment datasource details like server,database,username,password and I want to use this MXD in test environment pointing to test datasource details. I have created a Add-In button. On click on this button, ArcMap Database Connection windows pops up asking database details to which layer should point in test environment. Once user add the details I capture this information in IWorkspace workspace:

//Code for popping up a window to ask user for datasource details

IPropertySet propertySet = new PropertySetClass();
propertySet.SetProperty("SERVERINSTANCE", "sde:sqlserver:devserver"); //sde:sqlserver:(servername)
propertySet.SetProperty("dbclient", "SQLServer");
propertySet.SetProperty("DATABASE", "databasename"); //(databasename)
Type factoryType = Type.GetTypeFromProgID("esriDataSourcesGDB.SdeWorkspaceFactory");
IWorkspaceFactory workspaceFactory = (IWorkspaceFactory)Activator.CreateInstance(factoryType);
IWorkspace targetWorkspace = workspaceFactory.Open(propertySet, 0);     

In below code, I am trying to access layer's workspace connection properties and then trying to set it. I dont know how to proceed further with the code.

//Code for trying to set layer datasource.

IDocument doc = ArcMap.Application.Document;
IMxDocument mxDoc = doc as IMxDocument;
IMap map = mxDoc.FocusMap;            
ILayer layer = map.get_Layer(0);// Layer[0]; 
ESRI.ArcGIS.Carto.IFeatureLayer featureLayer = (ESRI.ArcGIS.Carto.IFeatureLayer)layer;
ESRI.ArcGIS.Geodatabase.IFeatureClass featureClass = featureLayer.FeatureClass;
ESRI.ArcGIS.Geodatabase.IDataset dataSet = (ESRI.ArcGIS.Geodatabase.IDataset)featureClass;                  
ESRI.ArcGIS.esriSystem.IPropertySet propertySet = dataSet.Workspace.ConnectionProperties;

dataSet.Workspace.ConnectionProperties.SetProperty("Server", "testservername"); 

Answer 1

I managed to do it using the below code:

private void ChangeDataSource(IWorkspace targetWorkspace)
        {
            IDocument doc = ArcMap.Application.Document;
            IMxDocument mxDoc = doc as IMxDocument;
            ESRI.ArcGIS.Carto.IMap map = mxDoc.FocusMap;
            ESRI.ArcGIS.Carto.ILayer layer = map.get_Layer(0);

            var dataLayer = (ESRI.ArcGIS.Carto.IDataLayer)layer;
            var datasetName = (IDatasetName)dataLayer.DataSourceName;
            var newWorkspaceName = (IWorkspaceName)((IDataset)targetWorkspace).FullName;

            datasetName.WorkspaceName = newWorkspaceName;            
            dataLayer.DataSourceName = (IName)datasetName; ;
            layer = (ESRI.ArcGIS.Carto.ILayer)dataLayer;            
        }