求助…………簡單的C#問題（資料庫連接）

在下新手，
寫了幾段段C#代碼，都是同一類型錯誤

“從索引 52 處開始，初始化字串的格式不符合規範。”

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;

namespace StudentInfonation
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
string strCon = "Provider = Microsoft.Jet.OLEDB.4.0 ; Data Source =D;//StudentInformation.mdb";
OleDbConnection myconn = new OleDbConnection(strCon);（運行時 點擊登陸，此處出錯）
myconn.Open();

string strSql = "select count(*) from main where name='" + this.textBox_name.Text + "'and Password='" + this.textBox_Password.Text + "'";
OleDbCommand cmd = new OleDbCommand(strSql, myconn);
if (Convert.ToByte(cmd.ExecuteScalar()) > 0)
{ this.label1.Text = "登陸成功！"; }
else
{ this.label1.Text = "登陸失敗！"; }

myconn.Close();
if(this.label1 .Text =="登陸成功！")
{
Form1 dlg0=new Form1();
dlg0 .ShowDialog ();
}
}
}
}

麻煩大俠幫忙指點一下·~~多謝··