是什么阻止组合框SelectedValue设置?

Question

我有几个组合框，所有类似的代码，只有一个，CustomerSelector。SelectedValue不工作。我甚至试过这样设置这个值:CustomerSelector.SelectedValue=32.

此方法用于将所有项目信息加载到窗体中，并在窗体Load事件中调用。数据似乎加载良好，我甚至加载'id'到DisplayMember来验证。

有什么想法是阻止SelectedValue设置?

void loadProjectInfo()
{
if (isProjectInfoLoaded == false)
{
try
{
DataTable dt4 = new DataTable();
DBConnector db4 = new DBConnector();
db4.query = "SELECT * FROM s1_pm_project WHERE id=" + JobID;
dt4 = db4.getDataTable();
DataRow PMProject = dt4.Rows[0];
ProjectNameTextbox.Text = PMProject["ProjectName"].ToString();
this.Text = ProjectNameTextbox.Text;
ProjectAddressTextbox.Text = PMProject["Address"].ToString();
ProjectAddressCity.Text = PMProject["City"].ToString();
ProjectAddressState.DataSource = USStates.States();
ProjectAddressState.ValueMember = "Abbreviations";
ProjectAddressState.DisplayMember = "Abbreviations";
ProjectAddressState.SelectedIndex = -1;
if (!Convert.IsDBNull(PMProject["State"]))
ProjectAddressState.SelectedValue = PMProject["State"].ToString();
ProjectAddressPostalCode.Value = (!Convert.IsDBNull(PMProject["ZipCode"])) ? Convert.ToInt32(PMProject["ZipCode"]) : 00000;
DBConnector db5 = new DBConnector();
db5.query = "SELECT id, Name FROM s1_customer ORDER BY Name ASC";
CustomerSelector.DisplayMember = "Name";
CustomerSelector.ValueMember = "id";
CustomerSelector.DataSource = db5.getDataTable();
CustomerSelector.SelectedIndex = -1;
//if (!Convert.IsDBNull(PMProject["CustomerID"]))
//    CustomerSelector.SelectedValue = Convert.ToInt32(PMProject["CustomerID"]);
CustomerSelector.SelectedValue=32;

DBConnector db1 = new DBConnector();
db1.query = "SELECT id, description FROM s1_app_status WHERE id < 2";
ProjectInfo_Status.DataSource = db1.getDataTable();
ProjectInfo_Status.DisplayMember = "description";
ProjectInfo_Status.ValueMember = "id";
ProjectInfo_Status.SelectedValue = Convert.ToInt32(PMProject["IsActive"]);
DBConnector db2 = new DBConnector();
db2.query = "SELECT id, description FROM s1_pm_roll";
ProjectInfoRollSelector.DataSource = db2.getDataTable();
ProjectInfoRollSelector.ValueMember = "id";
ProjectInfoRollSelector.DisplayMember = "description";
ProjectInfoRollSelector.SelectedIndex = -1;
if (Convert.ToInt32(PMProject["RollID"]) > 0)
ProjectInfoRollSelector.SelectedValue = Convert.ToInt32(PMProject["RollID"]);
DBConnector db3 = new DBConnector();
db3.query = "SELECT id, fullname FROM s1_user WHERE id>1";
ProjectInfoPMSelector.DataSource = db3.getDataTable();
ProjectInfoPMSelector.ValueMember = "id";
ProjectInfoPMSelector.DisplayMember = "fullname";
ProjectInfoPMSelector.SelectedIndex = -1;
if (Convert.ToInt32(PMProject["PMID"]) > 0)
ProjectInfoPMSelector.SelectedValue = Convert.ToInt32(PMProject["PMID"]);

ProjectInfoJobNoTextbox.Text = PMProject["JobNo"].ToString();
ProjectInfoValueTextbox.Value = Convert.ToDecimal(PMProject["ApproxValue"]);
if (!Convert.IsDBNull(PMProject["StartDate"]))
StartDateSelector.Value = Convert.ToDateTime(PMProject["StartDate"]);
if (!Convert.IsDBNull(PMProject["ProjectedEndDate"]))
ProjectedEndDateSelector.Value = Convert.ToDateTime(PMProject["ProjectedEndDate"]);
if (!Convert.IsDBNull(PMProject["EndDate"]))
EndDateSelector.Value = Convert.ToDateTime(PMProject["EndDate"]);
CustomerPOTextbox.Text = PMProject["CustomerPO"].ToString();
SalesTaxRateTextbox.Value = Convert.ToDecimal(PMProject["SalesTaxRate"]);
if (!Convert.IsDBNull(PMProject["WarrantyBegin"]))
WarrantyBegin.Value = Convert.ToDateTime(PMProject["WarrantyBegin"]);
if (!Convert.IsDBNull(PMProject["WarrantyEnd"]))
WarrantyEnd.Value = Convert.ToDateTime(PMProject["WarrantyEnd"]);

loadContactList();
}
catch (Exception ex)
{
Errors.Exception(ex);
}
isProjectInfoLoaded = true;
}
}

这是SELECT id, Name FROM s1_customer ORDER BY Name ASC的输出:

<表类>id名称tbody><<tr>2218-8谢尔曼橡树206Alejo卢戈233Americo建筑商,LLC235AMS Solutions, Inc1ARRIS Builders, Inc.209克里斯喷射器105CME制冷控制系统53海岸线规定117Cortech Construction, Inc6Development Support Services, Inc.146东湾餐饮供应有限公司31的健身狂热7支点建设32Hardesty,Associates Inc .135霍华德电器、Inc .9J Ray Construction10J& L金属制品12Jahanna L. Nichols Interior Design, Inc69James Barb Construction, Inc61JRE建设,Inc .13Kamran和公司,Inc .15熟食店分销商,Inc .98Lovisa America, LLC40移动客户120N电晕180N SANTA CLARA5N SERVICE SALE129Orangecrest Properties LLC223其他客户78太平洋Westline Inc .

问题最终与数据库有关，特别是s1_customer的id字段。由于某种原因，它具有'unsigned'属性。当它被删除后，一切都像预期的那样工作。