.NET读取Office文件内容（word、excel、ppt）

using Microsoft.Office.Core;
using Word = Microsoft.Office.Interop.Word;
using Excel = Microsoft.Office.Interop.Excel;
using PowerPoint = Microsoft.Office.Interop.PowerPoint;

public string ReadFile()
{
string text = string.Empty;
Word.ApplicationClass app = null;
Word.Document doc = null;
object readOnly = true;
object missing = System.Reflection.Missing.Value;
object fileName = this.FileInstance.FullName;
try
{
app = new Microsoft.Office.Interop.Word.ApplicationClass();
doc = app.Documents.Open(ref fileName, ref missing, ref readOnly, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing);
text = doc.Content.Text.Replace("\r", string.Empty).Replace("\n", string.Empty).Replace("\t", string.Empty);
}
catch
{ }
finally
{
doc.Close(ref missing, ref missing, ref missing);
doc = null;
app.Quit(ref missing, ref missing, ref missing);
app = null;
}
return text;
}

public string ReadFile()
{
string text = string.Empty;
Excel.ApplicationClass app = null;
Excel.Workbook book = null;
object readOnly = true;
object missing = System.Reflection.Missing.Value;
object fileName = this.FileInstance.FullName;
try
{
app = new Microsoft.Office.Interop.Excel.ApplicationClass();
book = app.Workbooks.Open(fileName.ToString(), missing, readOnly, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing);
foreach (Excel.Worksheet sheet in book.Sheets)
{
for (int i = ; i <= sheet.UsedRange.Cells.Rows.Count; i++)
{
for (int j = ; j <= sheet.UsedRange.Cells.Columns.Count; j++)
{
text += ((Excel.Range)sheet.Cells[i, j]).Text.ToString().Replace("\r", string.Empty).Replace("\n", string.Empty).Replace("\t", string.Empty) + " ";
}
}
}
}
catch
{ }
finally
{
book.Close(missing, fileName, missing);
book = null;
app.Quit();
app = null;
}
return text;
}

public override string ReadFile()
{
string text = string.Empty;
PowerPoint.ApplicationClass app = null;
PowerPoint.Presentation pp = null;
object readOnly = true;
object missing = System.Reflection.Missing.Value;
object fileName = this.FileInstance.FullName; try
{
app = new Microsoft.Office.Interop.PowerPoint.ApplicationClass();
pp = app.Presentations.Open(fileName.ToString(), Microsoft.Office.Core.MsoTriState.msoTrue, Microsoft.Office.Core.MsoTriState.msoFalse, Microsoft.Office.Core.MsoTriState.msoFalse); foreach (PowerPoint.Slide slide in pp.Slides)
{
foreach (PowerPoint.Shape shape in slide.Shapes)
{
text += shape.TextFrame.TextRange.Text.Replace("\r", string.Empty).Replace("\n", string.Empty).Replace("\t", string.Empty) + " ";
}
}
}
catch
{ }
finally
{
pp.Close();
pp = null;
app.Quit();
app = null;
} return text;
}