我该如何解决? [英] How can i fix that ?

问题描述

当图像存在于数据库中时，它将正确显示在pictureBox上.
如果图像不存在，则显示错误.

代码就在这里！

When the image exists at the database , It shows correctly at pictureBox.
If the image doesn''t exist, it shows error.

The Code is Here !

Private Sub gdCompany_CellClick_1(ByVal sender As System.Object, ByVal e As Telerik.WinControls.UI.GridViewCellEventArgs) Handles gdCompany.CellClick
      btnSave.Text = "ျပင္ရန္"
      picCompanyLogo.Visible = True
      txtCompanyName.Text = gdCompany.CurrentRow.Cells(1).Value.ToString()
      txtDescription.Text = gdCompany.CurrentRow.Cells(2).Value.ToString()
      txtPhoneNo.Text = gdCompany.CurrentRow.Cells(3).Value.ToString()
      txtFaxNo.Text = gdCompany.CurrentRow.Cells(4).Value.ToString()
      txtEmail.Text = gdCompany.CurrentRow.Cells(5).Value.ToString()
      txtWebsite.Text = gdCompany.CurrentRow.Cells(6).Value.ToString()
      ddlBankName.SelectedValue = Convert.ToInt32(gdCompany.CurrentRow.Cells(7).Value.ToString())
      ddlBankBranch.SelectedValue = Convert.ToInt32(gdCompany.CurrentRow.Cells(8).Value.ToString())
      txtBankAccountNo.Text = gdCompany.CurrentRow.Cells(9).Value.ToString()
      txtAddress.Text = gdCompany.CurrentRow.Cells(10).Value.ToString()
      Try
          'Get image data from gridview column.
          Dim imageData As Byte() = DirectCast(gdCompany.CurrentRow.Cells(15).Value, Byte())
          'Initialize image variable
          Dim newImage As Image
          'Read image data into a memory stream
          Using ms As New MemoryStream(imageData, 0, imageData.Length)
              ms.Write(imageData, 0, imageData.Length)
              'Set image variable value using memory stream.
              newImage = Image.FromStream(ms, True)
          End Using
          'set picture
          picCompanyLogo.Image = newImage
      Catch ex As Exception
          MessageBox.Show(ex.ToString())
          txtCompanyName.Focus()
      End Try
  End Sub

推荐答案

注释MessageBox:

Comment the MessageBox :

...
        Catch ex As Exception
            'MessageBox.Show(ex.ToString()) 'commented the message box
            txtCompanyName.Focus()
        End Try

我建​​议检查gdCompany.CurrentRow.Cells(15).Value为null的可能性，然后尝试将其强制转换为字节数组并尝试填充pictureBox.

更新:

I suggest checking for the possibility of gdCompany.CurrentRow.Cells(15).Value being null before you try to cast it to a byte array and try to populate the pictureBox.

Update:

if(gdCompany.CurrentRow.Cells(15).Value != null)
{
//your code here..
}

这是我的工作，当数据库中不存在该图像时，我想在我的资源中显示一个名为"unknownUser"的示例图像.

here is what i do, when if the image is not present in database i want to show a sample image,named "unknownUser" in my resources.

Private Sub DataGridView1_DataError(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewDataErrorEventArgs) Handles DataGridView1.DataError
        If e.ColumnIndex = 1 Then
            Dim cell As DataGridViewImageCell = DataGridView1.Rows(e.RowIndex).Cells(1)
            cell.Value = My.Resources.UnknownUser
        End If
    End Sub

因此，如果使用此选项，则网格中将不会出现任何错误的"X"图像，并且您的代码也不会引发任何异常.

so if you use this, there wont be any error "X" image in your grid, and your code wont throw any exception at all.

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