通过asp.net c#保存画布图像

<canvas id="myCanvas" width="500" height="500"></canvas>

<button onclick="saveImage()">保存图像</button>

function saveImage() {
  var canvas = document.getElementById("myCanvas");
  var image = canvas.toDataURL("image/png");
  var link = document.createElement('a');
  link.href = image;
  link.download = "canvas_image.png";
  link.click();
}

protected void btnSave_Click(object sender, EventArgs e)
{
    string base64Image = Request.Form["imageData"];
    byte[] bytes = Convert.FromBase64String(base64Image.Split(',')[1]);
    string filePath = Server.MapPath("~/Images/canvas_image.png");
    File.WriteAllBytes(filePath, bytes);
}

protected void Page_Load(object sender, EventArgs e)
{
    string filePath = Server.MapPath("~/Images/canvas_image.png");
    imgCanvas.ImageUrl = filePath;
}