{“你调用的对象是空的。”}

Question

使用 C# 创建一个 ASP.NET 表单，我遇到了这个错误，我不知道它的错误是什么。一切都很好，但是当我按下保存按钮时，它给了我这个错误：

     NulllRefrenceException was unhandled by user code
    {"Object reference not set to an instance of an object."}
Object reference not set to an instance of an object.

代码：

     protected void Button8_Click(object sender, EventArgs e)
    {
         SqlConnection cnn = new SqlConnection();
         cnn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["sqlAddSave"].ConnectionString;
    cnn.Open();
    SqlCommand cmd = new SqlCommand();
    cmd.CommandText = "select * from  DisplayPP";
    cmd.Connection = cnn;
    SqlDataAdapter da = new SqlDataAdapter();
    da.SelectCommand = cmd;
    DataSet ds = new DataSet();
    da.Fill(ds, " DisplayPP ");
    SqlCommandBuilder cb = new SqlCommandBuilder(da);
    DataRow drow = ds.Tables["DisplayPP"].NewRow();
    drow["website"] = web.Text;
    drow["country"] = DropDownList1.SelectedItem.Text;
    drow["contact"] = TextBox144.Text;
    drow["cat"] = TextBox145.Text;
    drow["traff"] = TextBox146.Text;

    more text boxes as above

    ds.Tables["DisplayPP "].Rows.Add(drow);
    da.Update(ds, " DisplayPP ");
    string script = @"<script language=""javascript"">
    alert('Information have been Saved Successfully.......!!!!!.');
   </script>;";
    Page.ClientScript.RegisterStartupScript(this.GetType(), "myJScript1", script);
    }

请帮忙。

连接字符串：

<add name="sqlAddSave" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\PPTableDisplay.mdf;Integrated Security=True"
providerName="System.Data.SqlClient" />

异常

异常详情：System.NullReferenceException 未被用户处理 code HResult=-2147467261 Message=对象引用未设置为 对象的实例。来源=TestCRole StackTrace：在 TestCRole._Default.Button8_Click(Object sender, EventArgs e) in c:\Users\xxxxx\Documents\Visual Studio 2012\Projects\WindowsAzure2\TestCRole\Default.aspx.cs：第 60 行 System.Web.UI.WebControls.Button.RaisePostBackEvent（字符串 eventArgument) 在 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint，布尔型 includeStagesAfterAsyncPoint) 内部异常：

Answer 1

ds.Tables["DisplayPP "].Rows.Add(drow);

应该是这样的

ds.Tables["DisplayPP"].Rows.Add(drow);