[英]how to solve Fill: SelectCommand.Connection property has not been initialized
I have a class which I have written all my methods there. 我有一个课,我在那里写了我所有的方法。 then I have my firstpage of web application which I have some codes there.
然后我有我的第一页Web应用程序,我在那里有一些代码。 I face this
我面对这个
in the line : 在线:
sda.Fill(dsUsers.tblMembers);
here is my code so I hope u can help me: 这是我的代码,所以我希望你能帮助我:
namespace MosquesNetwork
{
public class cUsers2
{
SqlConnection scn;
SqlDataAdapter sda;
SqlCommandBuilder scb;
SqlCommand SqlStr;
public cUsers2()
{
SqlConnection scn = new SqlConnection (ConfigurationManager.ConnectionStrings["MosquesDBConnectionString"].ConnectionString);
sda = new SqlDataAdapter();
scb = new SqlCommandBuilder(sda);
}
public bool CheckUserName(string UserName)
{
DsUsers2 dsUsers=new DsUsers2();
bool Success;
string SqlStr="select * from tblUsers where Username='"+UserName+"' ";
sda.SelectCommand=new SqlCommand(SqlStr, scn);
sda.Fill(dsUsers.tblMembers);
sda.Fill(dsUsers.tblMembers);
Success=dsUsers.tblMembers.Rows.Count>0;
return Success;
}
then I have this code while the login button is pressed in webform: 然后我在webform中按下登录按钮时有这个代码:
protected void Button1_Click(object sender, EventArgs e)
{
if (txtuser.Text.Trim().Length>0 && txtpass.Value.Length>0 )
{
cUsers2 cUsers=new cUsers2();
DsUsers2 dsUser=new DsUsers2();
bool Success;
if (txtuser.Text.Trim()=="admin")
{
Success=cUsers.CheckAdminPass(txtuser.Text.Trim(),txtpass.Value.Trim());
if (Success)
{
Response.Redirect("WebForm2.aspx");
}
}
dsUser=cUsers.Checkpassword(txtuser.Text.Trim(), txtpass.Value.Trim(),out Success);
if(Success)
{
Session["ID"]=dsUser.tblMembers.Rows[0][dsUser.tblMembers.IDUserColumn].ToString();
System.Web.HttpContext.Current.Response.Redirect("frmProfile.aspx");
}
else lblerror.Text="invalid username & password";
}
}
Look at your constructor: 看看你的构造函数:
SqlConnection scn = new SqlConnection(...);
That's declaring a separate scn
local variable, so the scn
instance variable is staying as null. 这是声明一个单独的
scn
局部变量,因此scn
实例变量保持为null。 If you just change it to: 如果您只是将其更改为:
scn = new SqlConnection(...);
that may well fix the immediate problem. 这可能很好地解决了眼前的问题。 It's not a nice design in my view - I'd prefer to create the
SqlConnection
in a using
block where you actually need it - but that's what's going wrong for now... 这不是在我看来,一个不错的设计-我宁愿创建
SqlConnection
在using
块,你真的需要它-但是这是什么错误,现在...
I got also this problem. 我也遇到了这个问题。 after search the problem found that the object of connection that i have provide SqlDataAdapter is not Initialize so the connection passed as null
搜索后问题发现我提供SqlDataAdapter的连接对象不是Initialize,所以连接传递为null
//Try To Fetch The Value Like this...
protected void Search_Emp_Click(object sender, EventArgs e)
{
SqlCommand cmd;
SqlConnection con;
SqlDataAdapter ad;
con = new SqlConnection(); //making instance of SqlConnection
con.ConnectionString = ConfigurationManager.ConnectionStrings["cn"].ConnectionString; //Invoking Connection String
con.Open(); //Opening Connection
if (Ddl_Emp_Search.SelectedItem.Text == "Date Of Joining")
{
cmd = new SqlCommand("Select Emp_Name,Contact_No,City,Emp_Desig,Place_Code from emp_registration where Emp_Doj=@Emp_Doj",con);
cmd.Parameters.Add("@Emp_Doj", SqlDbType.NVarChar, 50).Value = TextBox1.Text;
}
else if (Ddl_Emp_Search.SelectedItem.Text == "Name")
{
cmd = new SqlCommand("Select Emp_Name,Place_Code,Emp_Code,Emp_Desig from emp_registration where Emp_Name=@Emp_Name", con);
cmd.Parameters.Add("@Emp_Name", SqlDbType.NVarChar, 50).Value = TextBox1.Text;
}
else if (Ddl_Emp_Search.SelectedItem.Text == "Employee Code")
{
cmd = new SqlCommand("Select Emp_Name,Contact_No,City,Emp_Desig,Place_Code from emp_registration where Emp_Code=@Emp_Code", con);
cmd.Parameters.Add("@Emp_Code", SqlDbType.NVarChar, 50).Value = TextBox1.Text;
}
else if (Ddl_Emp_Search.SelectedItem.Text == "City")
{
cmd = new SqlCommand("Select Emp_Name,Contact_No,City,Emp_Desig,Place_Code from emp_registration where City=@City", con);
cmd.Parameters.Add("@City", SqlDbType.NVarChar, 50).Value = TextBox1.Text;
}
else
{
Response.Write("There is Something Worng....");
}
ad = new SqlDataAdapter(cmd); // Here IS THE PROBLEM WHEN YOU DOES'NT PASS CMD (Command instance) to the Data Adapter then there is a problem of ( Fill: SelectCommand.Connection property has not been initialized)
DataSet ds = new DataSet();
ad.Fill(ds);
GridView1.DataSource = ds;
GridView1.DataBind();
}
Vishal Sir, If You are Getting that Problem then Be sure whether you are passing the 'cmd' to the SQL DATA ADAPTER. Vishal先生,如果您遇到了这个问题那么请确定您是否将'cmd'传递给SQL DATA ADAPTER。 for eg:
例如:
ad = new SqlDataAdapter(cmd);
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.