Question

您好我有一个问题，即使用bindingSource将数据传输到datagridview，我的代码如下;

string query= "SELECT a.id as id1,a.id2, a.system_id, CONCAT(b.path,a.image) as photo ,b.id as id5,b.name,b.path  FROM users a INNER JOIN systems b ON a.system_id=b.id  order by a.id DESC LIMIT 20";
            using (MySqlCommand cmd = new MySqlCommand(query, conn))
            {
                MySqlDataAdapter da = new MySqlDataAdapter(cmd);
                var dt = new System.Data.DataTable();
                da.Fill(dt);
                bindingSource1.DataSource = dt.Rows.Cast<DataRow>().Select(p => new aclass() { id = (p["id1"].ToString()),  Photo= Image.FromFile(p["photo enter code here"].ToString()) }).ToList();
                conn.Close();


            }

此功能获取图像路径并添加到列表并在datagridview中显示照片，但我的问题是如果这张照片被删除没有显示错误，如果这张照片被删除如何删除添加一张照片头像默认。如果存在照片显示原始照片。 Thnks

Answer 1

You need to check if the file exists first and then either load it from the path or from the avatar path. You can use these helper functions:

private string LoadImage(string imagePath) {
  return Image.FromFile(MapImagePath(imagePath));
}

private string MapImagePath(string imagePath) {
  if (string.IsNullOrEmpty(imagePath))
    imagePath = GetNoImagePath();
  else {
    if (!File.Exists(imagePath))
      imagePath = GetNoImagePath();
  }
  return imagePath;
}

private string GetNoImagePath() {
  return "D:\ProjectFolder\Images\NoImage.png";
}

And now you can call them from your code like this:

var data = dt.Rows.Cast<DataRow>().Select(p => new aclass() {
  id = (p["id1"].ToString()),
  Photo = LoadImage(p["photo enter code here"].ToString())
}).ToList();

Note: Of course, you can make the path to the avatar a constant instead of a function. The function could be useful if you have several avatars and you want to return one of them based on some conditions.

Answer 2

You need to check if the file exists first and then either load it from the path or from the avatar path.

string avaterPath=@"D:\Images\NoImage.png";
string query= "SELECT a.id as id1,a.id2, a.system_id, CONCAT(b.path,a.image) as photo ,b.id as id5,b.name,b.path  FROM users a INNER JOIN systems b ON a.system_id=b.id  order by a.id DESC LIMIT 20";
            using (MySqlCommand cmd = new MySqlCommand(query, conn))
            {
                MySqlDataAdapter da = new MySqlDataAdapter(cmd);
                var dt = new System.Data.DataTable();
                da.Fill(dt);
                bindingSource1.DataSource = dt.Rows.Cast<DataRow>().Select(p => new aclass() { id = (p["id1"].ToString()),  Photo=File.Exists(p["photo enter code here"].ToString())? Image.FromFile(p["photo enter code here"].ToString()):Image.FromFile(avaterPath) }).ToList();
                conn.Close();


            }

Answer 3

感谢大家，这是我的解决方案;

 string avaterPath=@"D:\Images\NoImage.png";
string query= "SELECT a.id as id1,a.id2, a.system_id, CONCAT(b.path,a.image) as photo ,b.id as id5,b.name,b.path  FROM users a INNER JOIN systems b ON a.system_id=b.id  order by a.id DESC LIMIT 20";
            using (MySqlCommand cmd = new MySqlCommand(query, conn))
            {
                MySqlDataAdapter da = new MySqlDataAdapter(cmd);
                var dt = new System.Data.DataTable();
                da.Fill(dt);
                bindingSource1.DataSource = dt.Rows.Cast<DataRow>().Select(p => new aclass() { id = (p["id1"].ToString()),  Photo=File.Exists(p["photo enter code here"].ToString())? Image.FromFile(p["photo enter code here"].ToString()):Image.FromFile(avaterPath) }).ToList();
                conn.Close();


            }

C＃datagridview绑定源与图像路径（如果不存在）

3 个答案: