主题：代码

加上判断即可，如

If Tables("焊工资质清单").Visible Then
    Dim dt1 As Date = Date.Today.AddDays(10)
    Dim dr1 As DataRow = DataTables("焊工资质清单").Find("实际有效日期 <= #" & dt & "#")
    If dr1 IsNot Nothing Then
        MessageBox.Show("焊工证书即将到期!","提示",MessageBoxButtons.OK,MessageBoxIcon.Information)
        Tables("焊工资质清单").Filter = "实际有效日期 <= #" & dt & "#"
        MainTable = Tables("焊工资质清单")
    End If
End If