private void LoadCaseInfomation(Document document, LoadCase loadCase)
{
    string loadCaseNumber;   //Store the load cases number
    StringBuilder information = new StringBuilder(10);

    // first get all the load case categories in a list
    List<Category> loadCaseCategories = new List<Category>();
    GetLoadCaseCategories(document, ref loadCaseCategories);

    //get the load case name
    information.Append("\nCase Name: " + loadCase.Name);

    //get the number of the load case
    Parameter caseNumber = loadCase.get_Parameter(BuiltInParameter.LOAD_CASE_NUMBER);
    if (null == caseNumber)
    {
        loadCaseNumber = "";
    }
    else
    {
        loadCaseNumber = caseNumber.AsInteger().ToString();
    }
    information.Append("\nCase Number: " + loadCaseNumber);

    //get the category of the load case
    Parameter caseCategoryid = loadCase.get_Parameter(BuiltInParameter.LOAD_CASE_CATEGORY);
    Autodesk.Revit.DB.ElementId loadCaseCategoryId = caseCategoryid.AsElementId();

    information.Append("\nCategory: " + GetCategoryName(loadCaseCategoryId, loadCaseCategories));

    //get the nature of load case
    Parameter caseNatureId = loadCase.get_Parameter(BuiltInParameter.LOAD_CASE_NATURE);
    Autodesk.Revit.DB.ElementId loadCaseNatureId = caseNatureId.AsElementId();
    LoadNature loadNature = document.GetElement(loadCaseNatureId) as LoadNature;
    information.Append("\nNature: " + loadNature.Name + "\n");

    //show the information to the user
    TaskDialog.Show("Revit",information.ToString());
}

private void GetLoadCaseCategories(Document document, ref List<Category> loadCaseCategories)
{
    //get all the categories of load cases
    Categories categories = document.Settings.Categories;
    Category caseCategory = categories.get_Item(BuiltInCategory.OST_LoadCases);
    CategoryNameMap categoryNameMap = caseCategory.SubCategories;
    System.Collections.IEnumerator iter = categoryNameMap.GetEnumerator();
    iter.Reset();
    while (iter.MoveNext())
    {
        Category temp = iter.Current as Category;
        if (null != temp)
        {
            loadCaseCategories.Add(temp);
        }
    }
}

/// <summary>
/// Get the category name according to the load case category id.
/// </summary>
private string GetCategoryName(Autodesk.Revit.DB.ElementId loadCaseCategoryId, List<Category> loadCaseCategories)
{
    string categoryName = "";

    foreach (Category category in loadCaseCategories)
    {
        if (category.Id.Equals(loadCaseCategoryId))
        {
            categoryName = category.Name;
            break;
        }
    }
    return categoryName;
}

Private Sub LoadCaseInfomation(document As Document, loadCase As LoadCase)
    Dim loadCaseNumber As String
    'Store the load cases number
    Dim information As New StringBuilder(10)

    ' first get all the load case categories in a list
    Dim loadCaseCategories As New List(Of Category)()
    GetLoadCaseCategories(document, loadCaseCategories)

    'get the load case name
    information.Append(vbLf & "Case Name: " & Convert.ToString(loadCase.Name))

    'get the number of the load case
    Dim caseNumber As Parameter = loadCase.Parameter(BuiltInParameter.LOAD_CASE_NUMBER)
    If caseNumber Is Nothing Then
        loadCaseNumber = ""
    Else
        loadCaseNumber = caseNumber.AsInteger().ToString()
    End If
    information.Append(vbLf & "Case Number: " & loadCaseNumber)

    'get the category of the load case
    Dim caseCategoryid As Parameter = loadCase.Parameter(BuiltInParameter.LOAD_CASE_CATEGORY)
    Dim loadCaseCategoryId As Autodesk.Revit.DB.ElementId = caseCategoryid.AsElementId()

    information.Append(vbLf & "Category: " & GetCategoryName(loadCaseCategoryId, loadCaseCategories))

    'get the nature of load case
    Dim caseNatureId As Parameter = loadCase.Parameter(BuiltInParameter.LOAD_CASE_NATURE)
    Dim loadCaseNatureId As Autodesk.Revit.DB.ElementId = caseNatureId.AsElementId()
    Dim loadNature As LoadNature = TryCast(document.GetElement(loadCaseNatureId), LoadNature)
    information.Append(vbLf & "Nature: " + loadNature.Name & vbLf)

    'show the information to the user
    TaskDialog.Show("Revit", information.ToString())
End Sub

Private Sub GetLoadCaseCategories(document As Document, ByRef loadCaseCategories As List(Of Category))
    'get all the categories of load cases
    Dim categories As Categories = document.Settings.Categories
    Dim caseCategory As Category = categories.Item(BuiltInCategory.OST_LoadCases)
    Dim categoryNameMap As CategoryNameMap = caseCategory.SubCategories
    Dim iter As System.Collections.IEnumerator = categoryNameMap.GetEnumerator()
    iter.Reset()
    While iter.MoveNext()
        Dim temp As Category = TryCast(iter.Current, Category)
        If temp IsNot Nothing Then
            loadCaseCategories.Add(temp)
        End If
    End While
End Sub

' <summary>
' Get the category name according to the load case category id.
' </summary>
Private Function GetCategoryName(loadCaseCategoryId As Autodesk.Revit.DB.ElementId, loadCaseCategories As List(Of Category)) As String
    Dim categoryName As String = ""

    For Each category As Category In loadCaseCategories
        If category.Id.Equals(loadCaseCategoryId) Then
            categoryName = category.Name
            Exit For
        End If
    Next
    Return categoryName
End Function