c# 未將物件引用設定到物件的例項 使用“new”關鍵字建立物件例項。在呼叫方法前通過檢查確定物件是否為null
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data.OleDb; using System.Data.SqlClient; using System.Drawing.Drawing2D; using System.Threading.Tasks;
namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); }
public static DataSet getData() { //開啟檔案 OpenFileDialog file = new OpenFileDialog(); file.Filter = "Excel(*.xlsx)| * .xlsx | Excel(*.xls)| * .xls"; file.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop); file.Multiselect = false; if (file.ShowDialog() == DialogResult.Cancel) return null; //判斷檔案字尾 var path = file.FileName; string fileSuffix = System.IO.Path.GetExtension(path); if (string.IsNullOrEmpty(fileSuffix)) return null; using (DataSet ds = new DataSet()) { //判斷的Excel檔案是2003版本還是2007年版本 string connString = ""; if (fileSuffix == ".xls") connString = "Provider = Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + path + ";" + ";Extended Properties= \"Excel 8.0; HDR = YES; IMEX = 1 \""; else connString = "Provider = Microsoft.ACE.OLEDB.12.0;" + "Data Source=" + path + ";" + ";Extended Properties= \"Excel 12.0; HDR = YES; IMEX = 1 \""; //讀取檔案 string sql_select = "SELECT * FROM [Sheet1$]"; using (OleDbConnection conn = new OleDbConnection(connString)) using (OleDbDataAdapter cmd = new OleDbDataAdapter(sql_select, conn)) { NewMethod1(conn); cmd.Fill(ds); } if (ds == null || ds.Tables.Count <= 0) return null; return ds; } } private static void NewMethod1(OleDbConnection conn) { conn.Open(); }
private void button1_Click(object sender, EventArgs e) { dataGridView1.DataSource = null; //每次開啟清空內容
dataGridView1.DataSource = NewMethod().Tables[0]; }
private DataSet NewMethod() { return getData(); }
private void button2_Click(object sender, EventArgs e) { Form2 frm2=new Form2();
frm2.frm2Para = dataGridView1.DataSource;
frm2.Show();
}
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading.Tasks; using System.Data.OleDb; using System.Data.SqlClient; using System.Drawing.Drawing2D;
namespace WindowsFormsApplication1 { public partial class Form2 : Form { public Form2() { InitializeComponent(); }
private Object _parameter = null;
public Object frm2Para { get { return _parameter; } set { _parameter = value; } }
private void CreateImage() { DataSet ds = frm2Para as DataSet; int i = 0; i = ds.Tables[0].Rows.Count;（錯誤提示） double[] a = new double[i]; i = 0; foreach (DataRow Row in ds.Tables[0].Rows) { a[i] = Convert.ToDouble(Row["FAI 17"]); Console.WriteLine("{0}", a[i]); i++; //string str = ds.Tables[0].Rows[i]["FAI 17"].ToString(); //Rows[i]["col1"]表示i行"col1"欄位 }
double[] b = a.Where(p => p < 0.01 & p >= 0.0097).ToArray(); double[] c = a.Where(p => p < 0.02 & p >= 0.01).ToArray(); double[] d = a.Where(p => p < 0.03 & p >= 0.02).ToArray(); double[] e = a.Where(p => p < 0.04 & p >= 0.03).ToArray(); double[] f = a.Where(p => p < 0.05 & p >= 0.04).ToArray(); double[] h = a.Where(p => p < 0.06 & p >= 0.05).ToArray(); double[] j = a.Where(p => p < 0.07 & p >= 0.06).ToArray(); double[] k = a.Where(p => p < 0.08 & p >= 0.07).ToArray(); double[] l = a.Where(p => p < 0.09 & p >= 0.08).ToArray(); double[] m = a.Where(p => p < 0.10 & p >= 0.09).ToArray(); double[] n = a.Where(p => p < 0.11 & p >= 0.10).ToArray(); double[] o = a.Where(p => p < 0.12 & p >= 0.11).ToArray(); double[] q = a.Where(p => p < 0.13 & p >= 0.12).ToArray(); double[] r = a.Where(p => p <= 0.5416 & p >= 0.13).ToArray();
int count1 = b.Length; int count2 = c.Length; int count3 = d.Length; int count4 = e.Length; int count5 = f.Length; int count6 = h.Length; int count7 = j.Length; int count8 = k.Length; int count9 = l.Length; int count10 = m.Length; int count11 = n.Length; int count12 = o.Length; int count13 = q.Length; int count14 = r.Length;
int width = 515, height = 510; //宣告寬和高 Bitmap bitmap = new Bitmap(width, height); //建立一個bitmap物件 Graphics g = Graphics.FromImage(bitmap); //建立graphics物件 try { g.Clear(Color.White); //使用clear方法使畫布為白色 //建立3個brush物件，用於填充顏色 Brush brush1 = new SolidBrush(Color.White); Brush brush2 = new SolidBrush(Color.Black); Brush brush3 = new SolidBrush(Color.Red); Brush brush4 = new SolidBrush(Color.Green); //建立2個font物件，用於設定字型 Font font1 = new Font("Courier New", 16, FontStyle.Bold); Font font2 = new Font("Courier New", 10); g.FillRectangle(brush1, 0, 0, width, height); //繪製背景圖 g.DrawString("資料分佈", font1, brush2, new Point(177, 20)); //繪製標題 //設定座標 Point p1 = new Point(162, 50); Point p2 = new Point(295, 50); g.DrawLine(new Pen(Color.Black), p1, p2); //繪製直線 //繪製文字 g.DrawString("0.0097~0.01:", font2, brush2, new Point(14, 70)); g.DrawString("0.01~0.02:", font2, brush2, new Point(30, 95)); g.DrawString("0.02~0.03:", font2, brush2, new Point(30, 120)); g.DrawString("0.03~0.04:", font2, brush2, new Point(30, 145)); g.DrawString("0.04~0.05:", font2, brush2, new Point(30, 170)); g.DrawString("0.05~0.06:", font2, brush2, new Point(30, 195)); g.DrawString("0.06~0.07:", font2, brush2, new Point(30, 220)); g.DrawString("0.07~0.08:", font2, brush2, new Point(30, 245)); g.DrawString("0.08~0.09:", font2, brush2, new Point(30, 270)); g.DrawString("0.09~0.10:", font2, brush2, new Point(30, 295)); g.DrawString("0.10~0.11:", font2, brush2, new Point(30, 320)); g.DrawString("0.11~0.12:", font2, brush2, new Point(30, 345)); g.DrawString("0.12~0.13:", font2, brush2, new Point(30, 370)); g.DrawString("0.13~0.5416:", font2, brush2, new Point(14, 395)); //繪製柱形圖 g.FillRectangle(brush3, 120, 70, count1, 17); g.FillRectangle(brush3, 120, 95, count2, 17); g.FillRectangle(brush3, 120, 120, count3, 17); g.FillRectangle(brush3, 120, 145, count4, 17); g.FillRectangle(brush3, 120, 170, count5, 17); g.FillRectangle(brush3, 120, 195, count6, 17); g.FillRectangle(brush3, 120, 220, count7, 17); g.FillRectangle(brush3, 120, 245, count8, 17); g.FillRectangle(brush3, 120, 270, count9, 17); g.FillRectangle(brush3, 120, 295, count10, 17); g.FillRectangle(brush3, 120, 320, count11, 17); g.FillRectangle(brush3, 120, 345, count12, 17); g.FillRectangle(brush3, 120, 370, count13, 17); g.FillRectangle(brush3, 120, 395, count14, 17);
//繪製所有區間的數量顯示 //g.DrawRectangle(new Pen(Color.Green), 10, 210, 280, 80); //繪製範圍框 g.DrawString(count1.ToString() + "個", font2, brush4, new Point(300, 70)); g.DrawString(count2.ToString() + "個", font2, brush4, new Point(300, 95)); g.DrawString(count3.ToString() + "個", font2, brush4, new Point(300, 120)); g.DrawString(count4.ToString() + "個", font2, brush4, new Point(300, 145)); g.DrawString(count5.ToString() + "個", font2, brush4, new Point(300, 170)); g.DrawString(count6.ToString() + "個", font2, brush4, new Point(300, 195)); g.DrawString(count7.ToString() + "個", font2, brush4, new Point(300, 220)); g.DrawString(count8.ToString() + "個", font2, brush4, new Point(300, 245)); g.DrawString(count9.ToString() + "個", font2, brush4, new Point(300, 270)); g.DrawString(count10.ToString() + "個", font2, brush4, new Point(300, 295)); g.DrawString(count11.ToString() + "個", font2, brush4, new Point(300, 320)); g.DrawString(count12.ToString() + "個", font2, brush4, new Point(300, 345)); g.DrawString(count13.ToString() + "個", font2, brush4, new Point(300, 370)); g.DrawString(count14.ToString() + "個", font2, brush4, new Point(300, 395));
pictureBox1.Image = bitmap; } catch (Exception ex) { MessageBox.Show(ex.Message); } }
private void Form2_Load(object sender, EventArgs e) { CreateImage(); }
} }
我用form1連線到excel並讀取資料，form2獲取讀取到的資料並設定區間對資料進行分類處理，然後生成柱形圖。但是我不知道為什麼標註的紅色部分報錯，網上查了原因，但是我不知道該怎麼修改，求大神幫忙