' - > ToString'左边的错误必须指向class / struct / union / generic类型 [英] error left of '->ToString' must point to class/struct/union/generic type

问题描述

我是视觉c ++编码的nwebie。在下面的代码我面临这个错误，我不知道如何解决这个问题，为什么会发生这种情况

 String ^ constring = L" datasource = 127.0.0.1; port = 3306; username = root; password = 1965" ;; 
 MySqlConnection ^ conDatabase = gcnew MySqlConnection（constring）; 
 MySqlCommand ^ cmdDatabase = gcnew MySqlCommand（" SELECT * FROM`database`.edata其中Username ='" + this-> username_txt-> Text +"'和password ='" + this- > password_txt->文字+ QUOT;';"，conDatabase）; 
 MySqlDataReader ^ myReader; 
 try 
 {
 conDatabase-> Open（）; 
 myReader = cmdDatabase-> ExecuteReader（）; 
 int count = 0; 
 while（myReader-> Read（））
 {
 count = count + 1; 
} 
 if（count == 1）
 {
 MessageBox :: Show（myReader-> Read（） - > ToString（））; ///此行是否引起了我所提到的错误
 this-> Hide（）; 
 MyForm1 ^ f1 = gcnew MyForm1（）; 
 f1-> ShowDialog（）; 
} 
 if（count> 1）
 {
 MessageBox :: Show（" duplicate username and password"）; 
} 
 else 
 {
 MessageBox :: Show（"用户名或密码错误）; 
} 
} 
 catch（Exception ^ ex）
 {
 MessageBox :: Show（ex-> Message）; 
} 
} 

请帮我弄清楚发生了什么。

解决方案

我是视觉c ++编码的nwebie。在下面的代码我面临这个错误，我不知道如何解决这个问题，为什么这个
发生
< pre class ="prettyprint"> String ^ constring = L" datasource = 127.0.0.1; port = 3306; username = root; password = 1965" ;;
MySqlConnection ^ conDatabase = gcnew MySqlConnection（constring）;
MySqlCommand ^ cmdDatabase = gcnew MySqlCommand（" SELECT * FROM`database`.edata其中Username ='" + this-> username_txt-> Text +"'和password ='" + this- > password_txt->文字+ QUOT;';"，conDatabase）;
MySqlDataReader ^ myReader;
try
{
conDatabase-> Open（）;
myReader = cmdDatabase-> ExecuteReader（）;
int count = 0;
while（myReader-> Read（））
{
count = count + 1;
}
if（count == 1）
{
MessageBox :: Show（myReader-> Read（） - > ToString（））; ///此行是否引起了我所提到的错误
this-> Hide（）;
MyForm1 ^ f1 = gcnew MyForm1（）;
f1-> ShowDialog（）;
}
if（count> 1）
{
MessageBox :: Show（" duplicate username and password"）;
}
else
{
MessageBox :: Show（"用户名或密码错误）;
}
}
catch（Exception ^ ex）
{
MessageBox :: Show（ex-> Message）;
}
}

请帮我弄清楚发生了什么以及如何解决这个问题。

I am a nwebie in visual c++ coding.In the following code I am facing this error,I don't know how to solve this and why is this happening

String^ constring = L"datasource=127.0.0.1;port=3306;username=root;password=1965";
		MySqlConnection^ conDatabase = gcnew MySqlConnection(constring);
		MySqlCommand ^ cmdDatabase = gcnew MySqlCommand(" SELECT * FROM `database`.edata where Username='"+this->username_txt->Text+"' and password='"+this->password_txt->Text+"';",conDatabase);
		MySqlDataReader^ myReader;
		try
		{
			conDatabase->Open();
			myReader = cmdDatabase->ExecuteReader();
			int count = 0;
			while (myReader->Read())
			{
				count = count + 1;
			}
			if (count == 1)
			{
				MessageBox::Show(myReader->Read()->ToString());///THIS LINE IS CAUSING ERROR WHICH I HAVE MENTIONED
				this->Hide();
				MyForm1^ f1 = gcnew MyForm1();
				f1->ShowDialog();
			}
			if (count > 1)
			{
				MessageBox::Show("duplicate username and password");
			}
			else
			{
				MessageBox::Show("wrong username or password");
			}
		}
		catch (Exception ^ex)
		{
			MessageBox::Show(ex->Message);
		}
	}

Please help me to figure out what's going on.

解决方案

I am a nwebie in visual c++ coding.In the following code I am facing this error,I don't know how to solve this and why is this happening

String^ constring = L"datasource=127.0.0.1;port=3306;username=root;password=1965";
		MySqlConnection^ conDatabase = gcnew MySqlConnection(constring);
		MySqlCommand ^ cmdDatabase = gcnew MySqlCommand(" SELECT * FROM `database`.edata where Username='"+this->username_txt->Text+"' and password='"+this->password_txt->Text+"';",conDatabase);
		MySqlDataReader^ myReader;
		try
		{
			conDatabase->Open();
			myReader = cmdDatabase->ExecuteReader();
			int count = 0;
			while (myReader->Read())
			{
				count = count + 1;
			}
			if (count == 1)
			{
				MessageBox::Show(myReader->Read()->ToString());///THIS LINE IS CAUSING ERROR WHICH I HAVE MENTIONED
				this->Hide();
				MyForm1^ f1 = gcnew MyForm1();
				f1->ShowDialog();
			}
			if (count > 1)
			{
				MessageBox::Show("duplicate username and password");
			}
			else
			{
				MessageBox::Show("wrong username or password");
			}
		}
		catch (Exception ^ex)
		{
			MessageBox::Show(ex->Message);
		}
	}

Please help me to figure out what's going on and how to solve this issue.

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