在表中插入多个值

下面的代码可以很好地在一行表中插入新值。但是当我尝试插入多个值时，那么在输出中，这些值会在表中保存两次。

请帮助我的代码，将工作插入多个值在我的表。

private void Form1_Load(object sender, EventArgs e)
 {
 String strConnection = "Data Source=HP''SQLEXPRESS;database=MK;Integrated Security=true";
 SqlConnection con = new SqlConnection(strConnection);
 try
 {
 con.Open();
 SqlCommand sqlCmd = new SqlCommand();
 sqlCmd.Connection = con;
 sqlCmd.CommandType = CommandType.Text;
 sqlCmd.CommandText = "Select table_name from information_schema.tables";
 SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
 DataTable dtRecord = new DataTable();
 sqlDataAdap.Fill(dtRecord);
 comboBox1.DataSource = dtRecord;
 comboBox1.DisplayMember = "TABLE_NAME";
 comboBox1.ValueMember = "TABLE_NAME";
 con.Close();
 }
 catch (Exception ex)
 {
 MessageBox.Show(ex.Message);
 }
 }
 private void dataGridView1_RowEnter(object sender, DataGridViewCellEventArgs e)
 {
 var collection = this.dataGridView1.Rows;
 string output = "";
 foreach (DataGridViewRow row in collection)
 {
 foreach (DataGridViewCell cell in row.Cells)
 {
 if (cell.Value != null)
 {
 output += cell.Value.ToString() + " ";
 this.Text = output;
 }
 }
 }
 }
 private void PopulateGridView(string tablename)
 {
 if (tablename == "System.Data.DataRowView")
 return;
 String strConnection = "Data Source=HP''SQLEXPRESS;database=MK;Integrated Security=true";
 SqlConnection con = new SqlConnection(strConnection);
 try
 {
 con.Open();
 SqlCommand sqlCmd = new SqlCommand();
 sqlCmd.Connection = con;
 sqlCmd.CommandType = CommandType.Text;
 sqlCmd.CommandText = "Select * from " + tablename;
 SqlDataAdapter sqlDataAdap = new SqlDataAdapter(sqlCmd);
 DataTable dtRecord = new DataTable();
 sqlDataAdap.Fill(dtRecord);
 dataGridView1.DataSource = dtRecord;
 con.Close();
 }
 catch (Exception ex)
 {
 MessageBox.Show(ex.Message);
 }
 }
 private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
 {
 if (comboBox1.SelectedValue != null)
 {
 PopulateGridView(comboBox1.SelectedValue.ToString());
 }
 }
 private void InsertInfo()
 {
 string connectionString = null;
 SqlConnection connection;
 SqlDataAdapter adapter = new SqlDataAdapter();
 connectionString = @"Data Source=HP'SQLEXPRESS;database=MK;Integrated Security=true";
 connection = new SqlConnection(connectionString);
        foreach (int rowIndex in lstNewRows)
        {

            string insrtQry = "insert into " + comboBox1.Text + " values(";
            foreach (DataGridViewCell cell in dataGridView1.Rows[rowIndex].Cells)
            {
                insrtQry += "'" + cell.Value.ToString() + "',";
            }
            insrtQry = insrtQry.TrimEnd(",".ToCharArray());
            insrtQry += ")";

 try
 {
 connection.Open();
 adapter.InsertCommand = new SqlCommand(insrtQry, connection);
 adapter.InsertCommand.ExecuteNonQuery();

 MessageBox.Show("Row inserted !! ");
 connection.Close();
 }
 catch (Exception ex)
 {
 MessageBox.Show(ex.ToString());
 }
 }
 }


 private void insert_Click(object sender, EventArgs e)
 {
 InsertInfo();
 }
 private void dataGridView1_DefaultValuesNeeded(object sender, DataGridViewRowEventArgs e)
 {
 lstNewRows.Add(e.Row.Index);
 }

 }
 }