Data is cutting when importing huge data from Excel cell into SQL server 2008

Hi ArunRajendra,
data lost randomly. some cells data is perfectly imported but some are not imported perfectly..

{string excelConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + filename + ";Extended Properties=Excel 12.0";
using (OleDbConnection connection = new OleDbConnection(excelConnectionString))
{
connection.Open();
DataTable dtSheetName = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
List<string> SubChapters = new List<string>();
SubChapters.Add("--Select--");
int count = 0;
for (int nSheetcount = 0; nSheetcount < dtSheetName.Rows.Count; nSheetcount++)
{
count++;
StringBuilder sSheetNAme = new StringBuilder();
sSheetNAme.Append(dtSheetName.Rows[nSheetcount]["TABLE_NAME"].ToString());
tablename = sSheetNAme.ToString();
string sQuery = "Select * from [" + tablename + "]";
OleDbCommand command = new OleDbCommand(sQuery, connection);
OleDbDataAdapter adapter = new OleDbDataAdapter(command);
if (sSheetNAme.ToString().LastIndexOf("'") == sSheetNAme.ToString().Length - 1)
{
sSheetNAme.Remove(sSheetNAme.Length - 2, 2);
sSheetNAme.Replace('#', '.');
}
else
{
sSheetNAme.Remove(sSheetNAme.Length - 1, 1);
sSheetNAme.Replace('#', '.');
}

if (sSheetNAme.ToString().IndexOf("'") == 0)
{
sSheetNAme.Remove(0, 1);
}

SubChapters.Add(sSheetNAme.ToString());

DataTable Dsheet = new DataTable();
adapter.Fill(Dsheet);
dataset.Tables.Add(Dsheet);
}
cmdSubChapters.DataSource = SubChapters;
}

i think it is not imported the data which is having large size i.e greater than 255 characters. Please let me know the solution for importing the large size cell data.