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string s = “”+chでうまく代入されない

2010-06-20 (Sun)
C++

char ch='A';
string s = ""+ch;
cout << s << endl;

これ実行すると，Aが出力されない．なーんでだ

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DataGridView の行を削除する

2010-05-12 (Wed)
C++

DataGridView->Rows->Clear() ではエラーになるでーす

DataSetをクリア、DataTableをクリア、などの方法でできるらしいだ。

http://social.msdn.microsoft.com/Forums/ja-JP/vbexpressja/thread/684a1430-8f4e-4ff4-bc85-739e279cf331

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DataSet + BindingNavigator + TextBox

2010-05-09 (Sun)
C++

Windows フォームのプログラミング

方法 : Windows フォームの BindingNavigator コントロールを使用して DataSet を移動する

#using <System.dll>
#using <System.Data.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>
#using <System.EnterpriseServices.dll>
#using <System.Transactions.dll>
#using <System.Xml.dll>

using namespace System;
using namespace System::Collections::Generic;
using namespace System::ComponentModel;
using namespace System::Data;
using namespace System::Drawing;
using namespace System::Data::SqlClient;
using namespace System::Windows::Forms;

// This form demonstrates using a BindingNavigator to display
// rows from a database query sequentially.
public ref class Form1 : public Form
{
    // This is the BindingNavigator that allows the user
    // to navigate through the rows in a DataSet.
    BindingNavigator^ customersBindingNavigator;

    // This is the BindingSource that provides data for
    // the Textbox control.
    BindingSource^ customersBindingSource;

    // This is the TextBox control that displays the CompanyName
    // field from the the DataSet.
    TextBox^ companyNameTextBox;

public:
    Form1()
    {
        // Set up the BindingSource component.
        this->customersBindingSource = gcnew BindingSource();
        this->companyNameTextBox = gcnew TextBox();
        this->customersBindingNavigator = gcnew BindingNavigator();
        this->customersBindingNavigator->BindingSource =
            this->customersBindingSource;
        this->customersBindingNavigator->Dock = DockStyle::Top;
        this->Controls->Add(this->customersBindingNavigator);

        // Set up the TextBox control for displaying company names.
        this->companyNameTextBox->Dock = DockStyle::Bottom;
        this->Controls->Add(this->companyNameTextBox);

        // Set up the form.
        this->Size = System::Drawing::Size(800, 200);
        this->Load += gcnew EventHandler(this, &Form1::Form1_Load);
    }

private:
    void Form1_Load(Object^ sender, EventArgs^ e)
    {
        // Open a connection to the database.
        // Replace the value of connectString with a valid
        // connection string to a Northwind database accessible
        // to your system.
        String^ connectString =
            "Integrated Security=SSPI;Persist Security Info=False;" +
            "Initial Catalog=Northwind;Data Source=localhost";
        SqlConnection^ connection = gcnew SqlConnection();
        connection->ConnectionString = connectString;
        connection->Open();

        // Execute the query.
        SqlCommand^ command = gcnew SqlCommand(
            "Select * From Customers", connection);
        SqlDataReader^ reader = command->ExecuteReader(
            CommandBehavior::CloseConnection);

        // Load the Customers result set into the DataSet.
        DataSet^ ds = gcnew DataSet("Northwind Customers");
        ds->Load(reader, LoadOption::OverwriteChanges,
            gcnew array<String^> {"Customers"});

        // Assign the DataSet as the DataSource for the
        // BindingSource.
        this->customersBindingSource->DataSource = ds->Tables[0];

        // Bind the CompanyName field to the TextBox control.
        this->companyNameTextBox->DataBindings->Add(gcnew Binding("Text",
            this->customersBindingSource, "CompanyName", true));
    }
};

http://msdn.microsoft.com/ja-jp/library/s4b01sz7%28VS.80%29.aspx