这是我的代码

SqlCommand cmd = new SqlCommand("spRegisterUser", con);
cmd.CommandType = CommandType.StoredProcedure;

SqlParameter username = new SqlParameter("@UserName", txtUserName.Text);

SqlParameter password = new SqlParameter("@Password", txtPassword);
SqlParameter email = new SqlParameter("@Email", txtEmail.Text);
SqlParameter userType = new SqlParameter("@UserType", SqlDbType.NVarChar, 200);
userType.Value = "Student";
cmd.Parameters.Add(username);
cmd.Parameters.Add(password);
cmd.Parameters.Add(email);
cmd.Parameters.Add(userType);

con.Open();

int ReturnCode = (int)cmd.ExecuteScalar(); //This is where it displays error message
if (ReturnCode == -1)

有什么想法吗？

这是错误信息

No mapping exists from object type System.Web.UI.WebControls.TextBox to a known managed provider native type.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: No mapping exists from object type System.Web.UI.WebControls.TextBox to a known managed provider native type.

Source Error:

Line 48:                     con.Open();
Line 49: 
Line 50:                     int ReturnCode = (int)cmd.ExecuteScalar();
Line 51:                     if (ReturnCode == -1)
Line 52:                     {

Source File: c:\Users\Mubashir\Documents\Visual Studio 2012\Projects\Sit302GroupProject\Sit302GroupProject\Registration\Registration.aspx.cs Line: 50

Stack Trace:

[ArgumentException: No mapping exists from object type System.Web.UI.WebControls.TextBox to a known managed provider native type.]
       System.Data.SqlClient.MetaType.GetMetaTypeFromValue(Type dataType, Object value, Boolean inferLen, Boolean streamAllowed) +2021139
       System.Data.SqlClient.SqlParameter.GetMetaTypeOnly() +5287377
       System.Data.SqlClient.SqlParameter.Validate(Int32 index, Boolean isCommandProc) +16
       System.Data.SqlClient.SqlCommand.SetUpRPCParameters(_SqlRPC rpc, Int32 startCount, Boolean inSchema, SqlParameterCollection parameters) +122
       System.Data.SqlClient.SqlCommand.BuildRPC(Boolean inSchema, SqlParameterCollection parameters, _SqlRPC& rpc) +78
       System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite) +1379
       System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite) +175
       System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +53
       System.Data.SqlClient.SqlCommand.ExecuteScalar() +149
       Sit302GroupProject.Registration.btnRegister_Click(Object sender, EventArgs e) in c:\Users\Mubashir\Documents\Visual Studio 2012\Projects\Sit302GroupProject\Sit302GroupProject\Registration\Registration.aspx.cs:50
       System.Web.UI.WebControls.Button.OnClick(EventArgs e) +9552602
       System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +103
       System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
       System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
       System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +35
       System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1724

这是存储过程

CREATE proc spRegisterUser
@Username nvarchar(100),
@Password nvarchar(200),
@Email  nvarchar(200),
@UserType  nvarchar(200),
as 
Begin 
Declare @Count int
Declare @ReturnCode int

Select @Count = COUNT(UserName)
from tblUsers where UserName = @UserName
If @COunt > 0
Begin 
Set @Return = -1
End
Else
Begin
Set @ReturnCode = 1
Insert into tblUsers values
(@UserName, @Password, @Email, @UserType)
End
Select @ReturnCode as ReturnValue
End

最佳答案

您正在传递作为 TextBox 对象的 txtPassword，因此您会遇到异常。

问题在行

SqlParameter password = new SqlParameter("@Password", txtPassword);

所以把你的代码改成

SqlParameter password = new SqlParameter("@Password", txtPassword.Text);

关于c# - 不存在从对象类型 System.Web.UI.WebControls.TextBox 到已知托管提供程序 native 类型的映射，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19212706/