当我按F5启动应用程序时，我收到c2227错误 我不知道如何解决它，---------------------------------------- -------------------------------- 输出：
1>------ Build started: Project: YM! Download Manager, Configuration: Debug Win32 ------
1> YM! Download Manager.cpp
1>c:\users\youssef\documents\visual studio 2010\projects\ym! download manager\ym! download manager\Form1.h(289): error C2227: left of '->Text' must point to class/struct/union/generic type
1>c:\users\youssef\documents\visual studio 2010\projects\ym! download manager\ym! download manager\Form1.h(290): error C2227: left of '->Text' must point to class/struct/union/generic type
1>c:\users\youssef\documents\visual studio 2010\projects\ym! download manager\ym! download manager\Form1.h(291): error C2227: left of '->Text' must point to class/struct/union/generic type
1>c:\users\youssef\documents\visual studio 2010\projects\ym! download manager\ym! download manager\Form1.h(292): error C2227: left of '->Value' must point to class/struct/union/generic type
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========`
代码： 的 Form1.h
#pragma once
namespace YMDownloadManager {
using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;
using namespace System::Net;
/// <summary>
/// Summary for Form1
/// </summary>
public ref class Form1 : public System::Windows::Forms::Form
{
public:
Form1(void)
{
InitializeComponent();
//
//TODO: Add the constructor code here
//
}
protected:
/// <summary>
/// Clean up any resources being used.
/// </summary>
~Form1()
{
if (components)
{
delete components;
}
}
private: System::Windows::Forms::GroupBox^ groupBox1;
protected:
private: System::Windows::Forms::Button^ button2;
private: System::Windows::Forms::Button^ button1;
private: System::Windows::Forms::TextBox^ textBox2;
private: System::Windows::Forms::TextBox^ textBox1;
private: System::Windows::Forms::Label^ label2;
private: System::Windows::Forms::Label^ label1;
private: System::Windows::Forms::GroupBox^ groupBox2;
private: System::Windows::Forms::ProgressBar^ progress;
private: System::Windows::Forms::Label^ label6;
private: System::Windows::Forms::Label^ label5;
private: System::Windows::Forms::Label^ label4;
private: System::Windows::Forms::Label^ label3;
private: System::Windows::Forms::Label^ bytesrecieved;
private: System::Windows::Forms::Label^ totalbytesrecieved;
private: System::Windows::Forms::Label^ percent;
private:
/// <summary>
/// Required designer variable.
/// </summary>
System::ComponentModel::Container ^components;
#pragma region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
void InitializeComponent(void)
{
System::ComponentModel::ComponentResourceManager^ resources = (gcnew System::ComponentModel::ComponentResourceManager(Form1::typeid));
this->groupBox1 = (gcnew System::Windows::Forms::GroupBox());
this->button2 = (gcnew System::Windows::Forms::Button());
this->button1 = (gcnew System::Windows::Forms::Button());
this->textBox2 = (gcnew System::Windows::Forms::TextBox());
this->textBox1 = (gcnew System::Windows::Forms::TextBox());
this->label2 = (gcnew System::Windows::Forms::Label());
this->label1 = (gcnew System::Windows::Forms::Label());
this->groupBox2 = (gcnew System::Windows::Forms::GroupBox());
this->percent = (gcnew System::Windows::Forms::Label());
this->bytesrecieved = (gcnew System::Windows::Forms::Label());
this->totalbytesrecieved = (gcnew System::Windows::Forms::Label());
this->progress = (gcnew System::Windows::Forms::ProgressBar());
this->label6 = (gcnew System::Windows::Forms::Label());
this->label5 = (gcnew System::Windows::Forms::Label());
this->label4 = (gcnew System::Windows::Forms::Label());
this->label3 = (gcnew System::Windows::Forms::Label());
this->groupBox1->SuspendLayout();
this->groupBox2->SuspendLayout();
this->SuspendLayout();
//
// groupBox1
//
this->groupBox1->Controls->Add(this->button2);
this->groupBox1->Controls->Add(this->button1);
this->groupBox1->Controls->Add(this->textBox2);
this->groupBox1->Controls->Add(this->textBox1);
this->groupBox1->Controls->Add(this->label2);
this->groupBox1->Controls->Add(this->label1);
this->groupBox1->Location = System::Drawing::Point(12, 12);
this->groupBox1->Name = L"groupBox1";
this->groupBox1->Size = System::Drawing::Size(299, 124);
this->groupBox1->TabIndex = 0;
this->groupBox1->TabStop = false;
//
// button2
//
this->button2->Font = (gcnew System::Drawing::Font(L"Franklin Gothic Medium", 8.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
static_cast<System::Byte>(0)));
this->button2->Location = System::Drawing::Point(268, 54);
this->button2->Name = L"button2";
this->button2->Size = System::Drawing::Size(25, 20);
this->button2->TabIndex = 7;
this->button2->Text = L"...";
this->button2->UseVisualStyleBackColor = true;
this->button2->Click += gcnew System::EventHandler(this, &Form1::button2_Click);
//
// button1
//
this->button1->Font = (gcnew System::Drawing::Font(L"Courier New", 8.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
static_cast<System::Byte>(0)));
this->button1->Location = System::Drawing::Point(110, 95);
this->button1->Name = L"button1";
this->button1->Size = System::Drawing::Size(75, 23);
this->button1->TabIndex = 6;
this->button1->Text = L"Download";
this->button1->UseVisualStyleBackColor = true;
this->button1->Click += gcnew System::EventHandler(this, &Form1::button1_Click);
//
// textBox2
//
this->textBox2->Location = System::Drawing::Point(63, 54);
this->textBox2->Name = L"textBox2";
this->textBox2->Size = System::Drawing::Size(205, 20);
this->textBox2->TabIndex = 5;
//
// textBox1
//
this->textBox1->Location = System::Drawing::Point(39, 25);
this->textBox1->Name = L"textBox1";
this->textBox1->Size = System::Drawing::Size(253, 20);
this->textBox1->TabIndex = 4;
//
// label2
//
this->label2->AutoSize = true;
this->label2->Font = (gcnew System::Drawing::Font(L"Courier New", 8.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
static_cast<System::Byte>(0)));
this->label2->Location = System::Drawing::Point(5, 57);
this->label2->Name = L"label2";
this->label2->Size = System::Drawing::Size(63, 14);
this->label2->TabIndex = 2;
this->label2->Text = L"Save To:";
//
// label1
//
this->label1->AutoSize = true;
this->label1->Font = (gcnew System::Drawing::Font(L"Courier New", 8.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
static_cast<System::Byte>(0)));
this->label1->Location = System::Drawing::Point(8, 28);
this->label1->Name = L"label1";
this->label1->Size = System::Drawing::Size(35, 14);
this->label1->TabIndex = 1;
this->label1->Text = L"URL:";
//
// groupBox2
//
this->groupBox2->Controls->Add(this->percent);
this->groupBox2->Controls->Add(this->bytesrecieved);
this->groupBox2->Controls->Add(this->totalbytesrecieved);
this->groupBox2->Controls->Add(this->progress);
this->groupBox2->Controls->Add(this->label6);
this->groupBox2->Controls->Add(this->label5);
this->groupBox2->Controls->Add(this->label4);
this->groupBox2->Controls->Add(this->label3);
this->groupBox2->Font = (gcnew System::Drawing::Font(L"Courier New", 8.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
static_cast<System::Byte>(0)));
this->groupBox2->Location = System::Drawing::Point(12, 152);
this->groupBox2->Name = L"groupBox2";
this->groupBox2->Size = System::Drawing::Size(299, 100);
this->groupBox2->TabIndex = 0;
this->groupBox2->TabStop = false;
this->groupBox2->Text = L"Status";
//
// percent
//
this->percent->AutoSize = true;
this->percent->Location = System::Drawing::Point(117, 11);
this->percent->Name = L"percent";
this->percent->Size = System::Drawing::Size(49, 14);
this->percent->TabIndex = 7;
this->percent->Text = L"label7";
//
// bytesrecieved
//
this->bytesrecieved->AutoSize = true;
this->bytesrecieved->Location = System::Drawing::Point(127, 29);
this->bytesrecieved->Name = L"bytesrecieved";
this->bytesrecieved->Size = System::Drawing::Size(0, 14);
this->bytesrecieved->TabIndex = 6;
//
// totalbytesrecieved
//
this->totalbytesrecieved->AutoSize = true;
this->totalbytesrecieved->Location = System::Drawing::Point(106, 55);
this->totalbytesrecieved->Name = L"totalbytesrecieved";
this->totalbytesrecieved->Size = System::Drawing::Size(0, 14);
this->totalbytesrecieved->TabIndex = 5;
//
// progress
//
this->progress->Location = System::Drawing::Point(6, 73);
this->progress->Name = L"progress";
this->progress->Size = System::Drawing::Size(287, 19);
this->progress->TabIndex = 4;
//
// label6
//
this->label6->AutoSize = true;
this->label6->Location = System::Drawing::Point(243, 55);
this->label6->Name = L"label6";
this->label6->Size = System::Drawing::Size(56, 14);
this->label6->TabIndex = 3;
this->label6->Text = L"Byte(s)";
//
// label5
//
this->label5->AutoSize = true;
this->label5->Location = System::Drawing::Point(8, 55);
this->label5->Name = L"label5";
this->label5->Size = System::Drawing::Size(91, 14);
this->label5->TabIndex = 2;
this->label5->Text = L"Total Bytes:";
//
// label4
//
this->label4->AutoSize = true;
this->label4->Location = System::Drawing::Point(243, 29);
this->label4->Name = L"label4";
this->label4->Size = System::Drawing::Size(56, 14);
this->label4->TabIndex = 1;
this->label4->Text = L"Byte(s)";
//
// label3
//
this->label3->AutoSize = true;
this->label3->Location = System::Drawing::Point(8, 29);
this->label3->Name = L"label3";
this->label3->Size = System::Drawing::Size(112, 14);
this->label3->TabIndex = 0;
this->label3->Text = L"Bytes Recieved:";
//
// Form1
//
this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
this->ClientSize = System::Drawing::Size(323, 264);
this->Controls->Add(this->groupBox2);
this->Controls->Add(this->groupBox1);
this->FormBorderStyle = System::Windows::Forms::FormBorderStyle::FixedSingle;
this->Icon = (cli::safe_cast<System::Drawing::Icon^ >(resources->GetObject(L"$this.Icon")));
this->Name = L"Form1";
this->Text = L"YM! Download Manager";
this->Load += gcnew System::EventHandler(this, &Form1::Form1_Load);
this->groupBox1->ResumeLayout(false);
this->groupBox1->PerformLayout();
this->groupBox2->ResumeLayout(false);
this->groupBox2->PerformLayout();
this->ResumeLayout(false);
}
#pragma endregion
private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {
WebClient^ client = gcnew WebClient();
client->DownloadProgressChanged += gcnew DownloadProgressChangedEventHandler(DownloadProgressChanged);
client->DownloadFileCompleted += gcnew AsyncCompletedEventHandler(DownloadComplete);
client->DownloadFileAsync(gcnew Uri(textBox1->Text), textBox2->Text);
}
private: System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e) {
bytesrecieved->BringToFront();
totalbytesrecieved->BringToFront();
progress->BringToFront();
percent->BringToFront();
bytesrecieved->Text = L"......................................";
totalbytesrecieved->Text = L".................................";
percent->Text = L"... %";
}
static void DownloadProgressChanged(System::Object^ sender, DownloadProgressChangedEventArgs^ e)
{
bytesrecieved->Text = e->BytesReceived.ToString();
totalbytesrecieved->Text = e->TotalBytesToReceive.ToString();
percent->Text = e->ProgressPercentage.ToString() + " %";
progress->Value = e->ProgressPercentage;
}
static void DownloadComplete(System::Object^ sender, AsyncCompletedEventArgs^ e)
{
MessageBox::Show("Download Has Completed Successfully!", "Message From Program",
MessageBoxButtons::OK, MessageBoxIcon::Information);
}
private: System::Void button2_Click(System::Object^ sender, System::EventArgs^ e) {
SaveFileDialog^ save = gcnew SaveFileDialog();
save->Title = "Choose A Location For The Download To Save To.";
if (save->ShowDialog() == Windows::Forms::DialogResult::OK)
{
textBox2->Text = save->FileName;
}
}
};
}
有什么想法解决这个问题？
答案 0 :(得分：1)
由于某种原因，您的事件处理程序被声明为static。这意味着，与所有静态成员函数一样，它们不能使用不合格的非静态成员。因此，不能使用名称bytesrecieved，totalbytesrecieved等（拼写错误的btw）。
您几乎总是希望事件处理程序使用非静态成员函数。
而不是
client->DownloadProgressChanged += gcnew DownloadProgressChangedEventHandler(DownloadProgressChanged);
你需要
client->DownloadProgressChanged += gcnew DownloadProgressChangedEventHandler(this, &Form1::DownloadProgressChanged);
并从static
DownloadProgressChanged关键字