There are several ways to open datasets (including raster datasets and mosaic datasets) using code. This is an easy task if you already know what kind of dataset you are trying to open. In the sample case here the user only provides a string, the code needs to do the rest.

My input form looks like this:

In the code I get the text string from the text box and pass it to my function to open the data. The goal is to return an opened dataset, or null, if nothing was found.

 private IDataset OpenDataset(string fullPath)
{
  IWorkspace ws = null;
  IDataset dataset = null;
   /* Main logic here */
   return dataset;
}

Next I check if the path fulfills my requirements. It would be easy to extend this for other paths, such as URLs.

if (fullPath.Contains("\"))
{
  /* Logic to open the data */
}
else{ MessageBox.Show("Invalid input string"); }

Assuming that the input path is acceptable, I check to determine what kind of data it is. First, I split the string into the path and the dataset name. Then I parse the path string to see what kind of workspace is given. For example, a file geodatabase will have a .gdb in the string.

string sWs = "", sDs = "";  sWs = System.IO.Path.GetDirectoryName(fullPath);
sDs = System.IO.Path.GetFileName(fullPath);
/* Data is in a personal geodatabase */
if (sWs.ToLower().Contains(".mdb")){ ws = OpenAccessDatabase(sWs); }
/* Data is in a file geodatabase */
else if (sWs.ToLower().Contains(".gdb")){ ws = OpenGeoDatabase(sWs); }
/* Assume data is a file on disk */
else{ ws = OpenRasterWorkspace(sWs); }

At this point I use helper functions for each kind of workspace. In the sample here, I will show the OpenGeoDatabase code since my sample input is for a file geodatabase.

private IWorkspace OpenGeoDatabase(string path)
{
  IWorkspace ws = null;
  try
  {
    Type factoryType =
      Type.GetTypeFromProgID("esriDataSourcesGDB.FileGDBWorkspaceFactory");
    IWorkspaceFactory wsFact = (IWorkspaceFactory)Activator.CreateInstance(factoryType);
    ws = wsFact.OpenFromFile(path, 0);
  }
  catch (Exception exc) { }
  return ws; }

Now we’re half way there. We have found the right workspace but still need to open the dataset correctly. Here I take a brute-force approach: iterating through the dataset name objects. The beauty is that I am not opening all the datasets, but simply looking for the right name— which is quick.
Note, that at this point I don’t know what kind of dataset my input is. It could be a raster dataset or a mosaic dataset (or something else). Thus, I go through the different kinds of datasets I am expecting (raster dataset and mosaic dataset in this example). I use the boolean done to quit once I’ve found the correct name.

IEnumDatasetName dsNameEnum = null;
IDatasetName dsName = null;
IName name = null;
bool done = false;
if (ws != null)
{
  /* Iterate through RasterDatasetNames to check if a match exists */
  dsNameEnum = ws.get_DatasetNames(esriDatasetType.esriDTRasterDataset);
  dsName = dsNameEnum.Next();
  while (dsName != null && done == false)
  {
    if (dsName.Name.ToUpper() == sDs.ToUpper())
    {
      name = (IName)dsName;
      dataset = (IDataset)name.Open();
      done = true;
    }
    dsName = dsNameEnum.Next();
  }
  /* Iterate through MosaicDatasetNames to check if a match exists */
  dsNameEnum = ws.get_DatasetNames(esriDatasetType.esriDTMosaicDataset);
  dsName = dsNameEnum.Next();
  while (dsName != null && done == false)
  {
    if (dsName.Name.ToUpper() == sDs.ToUpper())
    {
      name = (IName)dsName;
      dataset = (IDataset)name.Open();
      done = true;
    }
    dsName = dsNameEnum.Next();
  }
}

Once the dataset is opened we can do all kinds of things, including creating a layer or manipulating the dataset.
This example shows one way to open a dataset in code. There are many others.

• Accessing raster workspaces
• Accessing raster datasets 
• Accessing mosaic datasets
• Accessing raster catalogs
• Accessing image services
• Accessing WCS services
• Accessing raster datasets with subdatasets (such as HDF or NITF)

Happy Coding.
Robert Berger