求助：未将对象引用设置到对象的实例。

chenyf_72 2010-10-15 07:09:08

未将对象引用设置到对象的实例。
说明: 执行当前 Web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。

异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。

源错误:

行 21: if (FileName.Text.Trim()!="")
行 22: {
行 23: PictureDB picture = new PictureDB();
行 24: Stream pictureStream = upfile.PostedFile.InputStream;
行 25: byte[] pictureData = new byte[upfile.PostedFile.ContentLength];

源文件: d:\编程\处理数据库中的图片\Default.aspx.cs 行: 23

我有实例化啊！！！！！怎么回事啊？？

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chenyf_72 2010-10-15

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嗯，好像是这的问题！！

孟子E章 2010-10-15

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ConfigurationSettings.AppSettings["ConnectionString"]返回的是null
检查web.config里面的配置

chenyf_72 2010-10-15

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public class PictureDB
{
public PictureDB(){}
private readonly string ConnectionString = ConfigurationSettings.AppSettings["ConnectionString"].ToString();
public int AddPicture(String sPictureDesn, byte[] bPictureData, String sPictureType)
{
SqlConnection conn = new SqlConnection(ConnectionString);

SqlCommand myCommand = new SqlCommand("Pr_AddPicture", conn);
myCommand.CommandType = CommandType.StoredProcedure;

SqlParameter parameterPictureDesn = new SqlParameter("@PictureDesn", SqlDbType.VarChar, 50);
parameterPictureDesn.Value = sPictureDesn;
myCommand.Parameters.Add(parameterPictureDesn);

SqlParameter parameterPictureData = new SqlParameter("@PictureData", SqlDbType.Image);
parameterPictureData.Value = bPictureData;
myCommand.Parameters.Add(parameterPictureData);

SqlParameter parameterPictureType = new SqlParameter("@PictureType", SqlDbType.VarChar, 50);
parameterPictureType.Value = sPictureType;
myCommand.Parameters.Add(parameterPictureType);

SqlParameter parameterPictureID= new SqlParameter("@PictureID", SqlDbType.Int,4);
parameterPictureID.Direction = ParameterDirection.ReturnValue;
myCommand.Parameters.Add(parameterPictureID);

try
{
conn.Open();
}
catch (System.Exception ex)
{
throw new Exception(ex.Message, ex);
}
try
{
myCommand.ExecuteNonQuery();
}
catch (System.Exception ex)
{
throw new Exception(ex.Message, ex);
}
finally{
if (conn.State==ConnectionState.Open){
conn.Close();
}
}
return (int)parameterPictureID.Value;
}

public SqlDataReader GetSinglePicture(int nPictureID)
{
SqlConnection conn = new SqlConnection(ConnectionString);
SqlCommand myCommand = new SqlCommand("Pr_GetSinglePicture", conn);
myCommand.CommandType = CommandType.StoredProcedure;

SqlParameter parameterPictureID = new SqlParameter("@PictureID", SqlDbType.Int, 4);
parameterPictureID.Value = nPictureID;
myCommand.Parameters.Add(parameterPictureID);
SqlDataReader dr = null;
try
{
dr = myCommand.ExecuteReader(CommandBehavior.CloseConnection);
}
catch (System.Exception ex)
{
throw new Exception(ex.Message, ex);
}
return dr;
}

}

孟子E章 2010-10-15