c# - 单击按钮更新数据库

Question

我有一个按钮可以将数据更新到数据库中。

private void button4_Click(object sender, EventArgs e)
        {
            //need update code//
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "Data Source=PEWPEWDIEPIE\\SQLEXPRESS;Initial Catalog=master;Integrated Security=True";
            conn.Open();

            SqlDataAdapter daCount = new SqlDataAdapter("select iCount from ComDet where cName = @cName", conn);
            daCount.SelectCommand.Parameters.Add("@cName", SqlDbType.VarChar).Value = ListU.SelectedValue;

            DataTable dtC = new DataTable();
            daCount.Fill(dtC);
            DataRow firstRow = dtC.Rows[0];

            string x = firstRow["iCount"].ToString();
            int y = Int32.Parse(x);
            int z = y + 1;

            //SqlCeCommand cmdC = conn.CreateCommand();
            SqlCommand cmdC = conn.CreateCommand();
            cmdC.CommandText = "Update ComDet set iCount = '" + z + "', ViewTime = '" + lblTime.Text + "', LastView = '" + txtUser2.Text + "' Where cName = '" + ListU.SelectedValue.ToString() + "'";
                conn.Close();
}

但是我得到这个错误..

有人可以帮忙吗？

更新=

我已经将我的代码更改为

cmdC.CommandText = "Update ComDet set iCount = " + z + ", ViewTime = '" + lblTime.Text + "', LastView = '" + txtUser2.Text + "' Where cName = '" + ListU.SelectedValue.ToString() + "'";

但是现在的问题是，没有更新

数据库中的iCount是一个INT，值为0。viewtime 和 lastview 也没有更新。

我现在哪里出错了？

Answer 1

改变这个:

    cmdC.CommandText = "Update ComDet set iCount = '" + z + "', ViewTime = '" + lblTime.Text + "', LastView = '" + txtUser2.Text + "' Where cName = '" + ListU.SelectedValue.ToString() + "'";

到

    cmdC.CommandText = "Update ComDet set iCount = " + z + ", ViewTime = '" + lblTime.Text + "', LastView = '" + txtUser2.Text + "' Where cName = '" + ListU.SelectedValue.ToString() + "'";

您不需要在其周围加上撇号“'”，因为它是一个数字。那肯定会让你 string not in correct format 错误